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Occurrence, biology, damage potential and management of Heterodera Schachtii (Nematoda: Heteroderidae) in small-scale farming in the Western Cape Province, South AfricaVan Zyl, J. (Jacques) 12 1900 (has links)
Thesis (PhD (Agric))--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: During a survey in the greater Cape Flats Heterodera schachtii was found to be
widespread on cauliflower, Brussels sprouts, beetroot and cabbage. The numbers present
were above two eggs and juveniles per gram of soil, generally regarded as the economic
threshhold level of infestation and requiring control.
The damage potential of H schachtii on vegetables, as well as the ability of certain
weeds to serve as a source of infection on subsequent crop plantings was studied under
greenhouse conditions and resulted in a reduction of yield and root weight of crops.
Population densities of H schachtii increased significantly under favourable hosts like
cabbage where densities of 198 eggs and juveniles per gram of soil were reached. The
most commonly occurring weeds maintained nematode development and increased their
population densities. They can thus serve as alternative hosts in the absence of
susceptible hosts and should be routinely controlled.
The life cycle and biology of H schachtii was also studied. Penetration of plant tissue
and subsequent development on vegetables, weeds and trap crops were observed.
Penetration was successful on all crops tested reaching 37% and 52% at inoculum levels
of 22 and 11 juveniles per gram of soil, respectively. Subsequent development of H
schachtii on weeds and vegetables was similar, but in the case of cauliflower and black
nightshade as hosts, their life cycle was shorter in comparison to other crops.
The possible existence of varying susceptibility of crops to different populations of H
schachtii was examined by comparing the rates of penetration in crops and reproduction
of geographically isolated populations of H schachtii in the greater Cape Flats. When root penetration, virulence and juvenile emergence were examined, populations from
Lynedoch and Philippi were distinct from the other populations. Subsequently,
representative individuals of these populations were subjected to PCR-RFLP, but with
these techniques real differences between the various populations could not be adequately
detected.
The environmental parameters such as soil texture, temperature and pH on H schachtii
were investigated as to their influence on the root weight and yield of crops. Reductions
in the yield of beetroot and cabbage were observed with soil temperatures ranging
between 15 to 30°C. Migration and penetration of H schachtii juveniles declined with
an increase in clay and silt content of the soil. Above a 34% silt and clay content of soil,
no migration and penetration took place. Root penetration levels of 30% and higher were
reached with pH varying between 4.5 and 7.4. This resulted in a significant reduction in
yield of crops.
Crop rotation is an essential component of non-chemical control. In the case of H
schachtii, it required one host crop in four non-host rotational cycles to maintain the
population of the nematode in the soilless than three eggs and juveniles per gram of soil.
The inclusion of a trap crop reduced the population densities to below two eggs and
juveniles per gram of soil. It therefore also forms an integral part of a control strategy.
Solarization proved successful as a physical control method. Best results were obtained
in summer with clear polyethylene which led to a 97% reduction of infective juveniles.
This method can be applied during the late summer in the greater Cape Flats, just before
the onset of winter. This may safeguard future spring plantings. The need for effective control strategies in order to reduce the numbers of H schachtii is
of the utmost importance to ensure vegetable production in the future. Small-scale
farmers should therefore be educated in this respect. / AFRIKAANSE OPSOMMING: Heterodera schachtii het wydverspreid in 'n opname in die groter Kaapse Vlakte
voorgekom op beet, blomkool, Brusselse spruite en kopkool. Die nematode getalle by
alle lokaliteite was bo die algemeen aanvaarbare ekonomiese drempelwaarde van twee
eiers en larwes per gram grond wat beheer regverdig.
Die skadepotensiaal van H schachtii op groente, sowel as die vermoë van sekere
onkruide om as infeksie bronne te dien vir opvolgende gewasse, is in glashuise ondersoek
en het tot 'n verlaging in opbrengs en wortelmassa by gashere gelei. Die populasie
digthede van H schachtii het met die aanplant van geskikte gashere tot vlakke van 198
eiers en larvae per gram grond gestyg. Die mees algemeen voorkomende gasheeronkruide
het nematode ontwikkeling in stand gehou en selfs tot 'n populasie verhoging
gelei. Hierdie onkruide is 'n beperkende faktor vir die verbouing van groente aangesien
die onkruide as alternatiewe gasheer kan dien in die afwesigheid van gashere en
onkruidbeheer moet dus op 'n gereelde basis toegepas word.
Die lewenssiklus en biologie van H schachtii is ondersoek deurdat die penetrasie van
gasheer wortels en die daaropvolgende ontwikkeling op groente, onkruide en
vanggewasse vergelyk is. Penetrasie, vyf dae na inokulasie, is met alle gashere verkry
met 37% en 52% penetrasie met inokulum vlakke van 22 en 11 larwes per gram grond
onderskeidelik. Daaropvolgende ontwikkeling van H schachtii was soortgelyk op
groente en onkruide, maar blomkool en nastergal het as gashere 'n verkorte lewenssiklus
tot gevolg gehad.
Die moontlikheid van verskille in die virulensie van H schachtii is ondersoek deur die
penetrasie van gewasse en reproduksie vlakke van nematodes van nege verskillende geografies geskeide populasies in the groter Kaapse Vlakte te vergelyk. Die Lynedoch en
Philippi populasies het onderskeibare resultate gelewer ten opsigte van die populasies uit
die ander lokaliteite, maar geen verskille kon met PKR-RFLP aangetoon word nie.
Die invloed van omgewings parameters, grondtekstuur, temperatuur en pH, is op H
schachtii ondersoek ten opsigte van opbrengste en wortelmassa van gewasse.
Grondtemperature tussen 15°C - 30°C het tot die grootste daling in opbrengs gelei op
kopkool en beet. Migrasie en penetrasie het afgeneem met 'n toename in klei en slik
inhoud tot en met 'n klei en slik inhoud van 34%, waarna geen penetrasie en migrasie
voorgekom het nie. Wortelpenetrasie van 30% en hoër het voorgekom by pH vlakke van
tussen 4.5 - 7.4 met die gepaardgaande verlaging in opbrengs van gewasse.
Afwisseling van gewasse is 'n essensiële metode van nie-chemiese beheer van nematode
getalle in die grond. Die mees optimale rotasie ten opsigte van H schachtii beheer is met
die aanplanting van een gasheer gewas in vier gewas aanplantings verkry. Die insluiting
van 'n vanggewas in die gewas rotasie siklus het die nematode populasievlakke tot onder
twee per gram grond laat daal. Solarisasie is suksesvol uitgevoer met deurskynende
poli-etileen in die groter Kaapse Vlakte gedurende die somer met gevolglik 'n 97%
vermindering van die getalle infektiewe nematodes.
Effektiewe beheermaatreëls ten opsigte van H schachtii moet in die groter Kaapse
Vlakte ingestel word om groente-produksie in hierdie gebied te verseker. Kleinboere
moet in hierdie tegnieke opgelei word.
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An assessment of climate change science literacy and climate change pedagogical literacy of geography teachers in the Western CapeAnyanwu, Raymond Ndubisi 04 1900 (has links)
Thesis (PhD)--Stellenbosch University 2015. / ENGLISH ABSTRACT: This survey research employed a criterion-referenced multiple-choice questionnaire to
collect data from 194 FET Geography teachers in the Western Cape province to
assess their level of literacy in both climate change science and climate change
pedagogy, and to determine the influence of gender, age, qualification, specialisation,
experience, grade mostly taught, their experience in providing instruction on climate
change and the location of their school. Aspects of climate change science assessed
include: climate processes and probable causes of climate change; climate change
impacts; and climate change responses. Aspects of climate change pedagogy
assessed include: the aims and significance of climate change education; and
constructivist teaching principles and practice.
The collected data was analysed using percentage frequencies to determine the
teachers‟ level of literacy in climate change science and climate change pedagogy; the
Mann-Whitney and Kruskal-Wallis tests were used to determine the influence of the
mediating variables on climate change science literacy and climate change
pedagogical literacy, respectively. The results indicate that Geography teachers in the
Western Cape Province demonstrated „High‟ literacy in climate change science and
„Low‟ literacy in climate change pedagogy. Factors such as school location, gender,
age and teaching experience were found to have a significant influence on climate
change science literacy; whereas qualification, specialisation, grade mostly taught and
experience in providing instruction on climate change did not. Conversely, teaching
experience and grade mostly taught had a significant influence on climate change
pedagogical literacy; whereas school location, gender, age, qualification, specialisation
and experience in providing instruction on climate change did not. Based on these
findings, it is recommended that professional development interventions in climate
change pedagogy are required in order to expose Geography teachers to the aims and
significance of climate change education and methods of facilitating problem-based,
learner-centred instruction on climate change. / AFRIKAANSE OPSOMMING: Hierdie opnamenavorsing het gebruik gemaak van ‟n kriteriumverwysing- meerkeusige
vraelys om data by 194 VOO Aardrykskunde onderwysers in die Wes-Kaap provinsie
te versamel om hulle vlak van geletterdheid in beide die wetenskap en pedagogie van
klimaatsverandering te bepaal en om die invloed van geslag, ouderdom, kwalifikasie,
spesialisasie, ervaring, graad wat die meeste onderrig is, hulle ervaring van onderrig
oor klimaatsverandering en die ligging van hulle skool te bepaal. Aspekte van
klimaatsverandering wat geassesseer is, het klimaatsprosesse en moontlike oorsake
van klimaatsverandering, impakte van klimaatsverandering en reaksies op
klimaatsverandering ingesluit. Aspekte van die pedagogie van klimaatsverandering
wat geassesseer is, het die doelwitte en betekenisvolheid van opvoeding oor
klimaatsverandering en konstruktivistiese onderrigbeginsels en -praktyk ingesluit.
Die versamelde data is met persentasiefrekwensie geanaliseer om die onderwysers se
vlak van geletterdheid in die wetenskap en pedagogie van klimaatsverandering te
bepaal; die Mann-Whitney en Kruskal-Wallis toetse is gebruik om die invloed van
bemiddelende veranderlikes op geletterdheid met betrekking tot die wetenskap en
pedagogie van klimaatsverandering onderskeidelik te bepaal. Die resultate dui aan dat
Aardrykskunde-onderwysers in die Wes-Kaap „Hoë‟ geletterdheid in die wetenskap
van klimaatsverandering en „Lae‟ geletterdheid in die pedagogie van
klimaatsverandering getoon het. Faktore soos ligging van die skool, geslag, ouderdom
en onderrigervaring het ‟n betekenisvolle invloed op geletterdheid in
klimaatsverandering gehad, terwyl kwalifikasie, spesialisasie, graad wat die meeste
onderrig is en ervaring van onderrig oor klimaatsverandering nie so ‟n invloed gehad
het nie. In teenstelling het onderrigervaring en graad wat die meeste onderrig is, ‟n
betekenisvolle invloed op geletterdheid in klimaatsverandering gehad, terwyl ligging
van die skool, geslag, ouderdom, kwalifikasie, spesialisasie en ervaring van onderrig
oor klimaatsverandering nie so ‟n invloed gehad het nie. Op grond van hierdie
resultate kan gesê word dat professionele ontwikkelingsingrypings in die pedagogie
van klimaatsverandering nodig is om Aardrykskunde-onderwysers bloot te stel aan die
doelwitte en belangrikheid van onderwys oor klimaatsverandering en metodes om
probleemgebaseerde, leerdergesentreerde onderrig oor klimaatsverandering te
fasiliteer.
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Invasive perennial species in an agricultural area of the Western Cape Province : distribution and relationship with various land-use typesMidgley, John Claude 04 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: This project consists of two botanical investigations in an agricultural area of the Western Cape
Province. A farm known as De Rust, in the Elgin Valley, was used to sample the geographic location,
density, height and life stage of six prominent invasive plant species in various land-use categories.
In the first investigation, the density, height and age structures of the six invasive species populations
were analyzed. The density distribution of the six species was also displayed cartographically. Species
were then ranked according to the potential threat that they pose to the conservation of the remaining
natural areas on the farm. Results indicated that Acacia mearnsii and Acacia saligna are the major
invaders at De Rust and that Hakea sericea can be considered as an emerging invader.
The second investigation explores the statistical relationship between the various land-use categories
and density, height and age of the six prominent invaders identified in the first investigation. The loglikelihood
ratio analysis of observed frequencies resulted in statistically significant (P<0.01; P-values
range between 1.35 x 10-3 and 2.7 x 10-224) relationships between certain land-use types and certain
invasive species. A conclusion was reached that it could be useful to include land-use categories in
simulation models of invasive plant species distribution and spread. / AFRIKAANSE OPSOMMING: Hierdie projek behels twee botaniese ondersoeke in ‘n landbou gebied van die Weskaap. Die plaas
bekend as De Rust, in die Elgin Vallei, was gebruik vir die versameling van data te doen met die
geografiese ligging, plant digtheid, lengte en lewens stadium van ses prominente indringer plant
spesies in verskeie landgebruik kategorieë.
Die digtheid, lengte en ouderdomstruktuur van ses indringerspesies was in die eerste ondersoek
geanaliseer. Die verspreiding van digtheid was ook in kaarte uitgelê. Spesies was daarna volgens hulle
potentiële dreiging teen die bewaring van oorblywende natuurlike dele van die plaas in ‘n rangorde
geplaas. Resiltate dui aan dat Acacia mearnsii en Acacia saligna die belangrikste indringer plante op
De Rust is en dat Hakea sericea as ‘n opkomende indringer beskou kan word.
Die tweede ondersoek kyk na die verhouding tussen verskeie grondgebruik kategorië en die digtheid,
lengte en ouderdom van die ses prominente indringer spesies wat in die eerste ondersoek identifiseër
is. ‘n Log tipe ratios ontleding van bewaarde frekwensies het ‘n statisties belangrike uitkoms gehad
(P<0.01; P-waardes tussen 1.35 x 10-3 en 2.7 x 10-224) vir die verhoudings tussen sekere grondgebruik
tipes en sekere indringer spesies. Die gevolgtrekking was dat dit handig mag wees om grondgebruik
kategorieë in simulasies van indringer plant verspreiding te gebruik.
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Mite communities within Protea infructescences in South AfricaTheron, Natalie 03 1900 (has links)
Thesis (MScConEcol)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The role of mites as primary vectors of various fungi within Protea infructescences was recently confirmed and raised questions about their general diversity and their role within this unique niche. Although mites evidently form an integral part of Fynbos ecosystems and probably play a significant role in Protea population dynamics, there is a general void in our knowledge of mite diversity within the Cape Floristic Region. These organisms do not only affect ecological processes within the CFR, but also the economic value of Protea exports. This study sets out to describe mite communities within the infructescences of a variety Protea species. In the process, the role of various environmental variables and differences in host characteristics affecting these communities are also explored. A total of 24281 mite individuals, comprising of 36 morphospecies in 23 families, were collected from 16 surveyed Protea spp. Mite community structure and composition were significantly influenced by plant taxonomy, phenology and infructescence architecture in different Protea spp. At a temporal scale, infructescence age and season were influential factors on mite community structure. Collection locality significantly influenced mite communities within the infructescences of a single Protea sp. Host architecture had no influence on mite communities within a single host species. Geographic distance had no significant influence on mite community structure within Protea infructescences. This implies that factors particular to particular host species determine mite communities. These include factors such as the mode of pollination of the host plant, level of serotiny and plant life form. Numerous newly recorded mite species collected from Protea infructescences are also described in this study. An identification key to the Tydeidoidae of South Africa is provided here for the first time. This study forms a baseline dataset for future studies on the biodiversity of mites in this extremely diverse eco-region. / AFRIKAANSE OPSOMMING: Die rol van myte as primêre vektore van verskeie funguses binne Protea vrugtekoppe is onlangs bevestig, en het vrae laat ontstaan oor hulle algemene diversiteit en rol binne hierdie unieke nis. Alhoewel myte duidelik ‘n integrale deel vorm van Fynbos ekosisteme en waarskynlik ‘n belangrike rol speel in Protea populasie-dinamika, is daar ‘n algemene leemte in ons kennis van mytdiversiteit binne die Kaapse Floristiese Ryk (KFR). Hierdie organismes affekteer nie slegs ekologiese prosesse binne die KFR nie, maar ook die ekonomiese waarde van Protea-uitvoere.
Hierdie studie mik as vertrekpunt om die verkillende myt-gemeenskappe binne die vrugtekoppe van verskeie Protea spesies te beskryf. In die proses is die rol van verskillende omgewingsveranderlikes en verskille in gasheer kenmerke wat hierdie gemeenskappe affekteer, ook ondersoek. ‘n Totaal van 24281 myt individue, saamgestel uit 36 morfspesies in 23 families, mytgemeenskappe is beduidende beinvloed deur die taksonomie van die plant, die fenologie en die vrugtekop-argitektuur van verskillende Protea spesies. Op ‘n temporale skaal is gevind dat vrugtekop-ouderdom en seisoen beduidende faktore is in die samestelling van mytgemeenskapstruktuur. Versamel-lokaliteit het verder mytgemeenskappe binne die vrugtekoppe mytgemeenskappe binne ‘n enkele gasheerspesie getoon nie. Geografiese afstand het geen beduidende invloed op mytgemeenskapstruktuur binne Protea vrugtekoppe getoon nie. Dit faktore in soos die metode van bestuiwing van die gasheer plant, die vlak van saadhoudendheid van die Protea koppe en plant-lewensvorm. Verskeie nuwe myt spesies wat uit Protea vrugtekoppe versamel is, word ook in hierdie studie beskryf. ‘n Identifikasie-sleutel vir die Tydeidoidae van Suid-Afrika word verder vir die eerste keer hier verskaf. Hierdie studie vorm die basis datastel vir toekomstige studies van die biodiversiteit van myte in hierdie besonder diverse eko-omgewing.
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Funksionele bemagtiging van die opvoeder van volwassenes in die Wes-KaapJansen, Edward Henry 03 1900 (has links)
Thesis (MEdPsych (Educational Psychology))--University of Stellenbosch, 2009. / According to the latest available statistics, 9 million people in South Africa
are illiterate. A large number of these people did not attend school. This can
be attributed to a number of factors, amongst others no entry to any form of
schooling, economic realities and a expectation of low quality of life
It is especially after 1994 that Adult Basic Education and Training was
scrutinized in order to address the backlogs. A more closer investigation
has shown that the adult education centres at a convenient sample of 3
secondary schools in the Western Cape (N = 18) are merely an extension
of mainstream education, without taking into account the notion of the
Andragogy (The Teaching of Adults).
This study aims to determine guidelines to assist the educator of adults on
the path to empowerment, in order to help to ensure the above scientific accountability
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The geology and geochemistry of the Bridgetown Formation of the Malmesbury Group, Western Cape ProvinceSlabber, Nina 06 1900 (has links)
Thesis (MSc) -- Stellenbosch University , 1995. / ENGLISH ABSTRACT: A number of small greenstone bodies of the Bridgetown Formation are exposed as
elongated lenses and dykes within metasediments of the Malmesbury Group in the
Western Cape Province, South Africa. The Malmesbury Group is part of the
Neoproterozoic to Cambrian (Namibian) Saldania Subprovince which is the southern
continuation of a Pan-African mobile belt system.
A detailed geological and geochemical study was conducted on the largest outcrop
of the Bridgetown Formation, situated 20km east of the town Moorreesburg.
The Bridgetown Formation consists of a meta-volcano-sedimentary sequence that
experienced polyphase deformation and metamorphism up to the lower greenschist
facies. Tectonically, the Bridgetown Formation is included in the Boland tectonic
domain, east of the Piketberg-Wel lington fault zone that is suggested to run Skm
west of Heuningberg and subparallel to the Berg River. This agrees with Rabie's
(1974) original subdivision of the tectonic domains.
The Bridgetown Formation consists of: i) A basal unit of poorly differentiated
alkaline metabasalt with a within-plate tectonomagmatic fingerprint. ii) An
intermediate unit of poorly differentiated tholeiitic metabasalt, intruded by a younger
tholeiitic metabasite with a low degree of differentiation. Both members of the
intermediate unit have ocean-floor basalt (P-type MORB) and island arc basalt
fingerprints. iii) An upper unit of poorly differentiated as well as more evolved
alkaline metabasalts, interlayered with metatuff with an alkaline basaltic composition,
metasedimentary rocks with a marine origin, and graphitic schists and muscovitequartz
schists, both with a continental crust provenance. iv) An overlying
metasedimentary sequence including dolomite, massive and oolitic chert, jasper and
jaspilite.
The Bridgetown Formation probably also comprises a lower metamorphosed
ultramafic unit, indicated by the association of Ni- and Cr-rich talc bodies, Ni-and errich
banded chert, chlorite schist and small dolomite-talc-chlorite bodies at Spitskop,
situated directly northwest of the main greenstone body.
The sequence of eruptive stages and the geochemistry of the metavolcanics
resemble Hawaiian volcanism , indicated by an initial deep water stage of alkaline
magmatism, followed by main tholeiitic edifice and post-caldera alkaline magmatism.
Post-caldera alkaline magmatism occurred contemporaneously with deposition . of
sediments and chemical precipitates (carbonates and cherts).
The Bridgetown metavolcanics have no magmatic association with either the
Bloubergstrand volcanics or mafic and intermediate plutonic rocks in the
Malmesbury Group. However, some physical and geochemical similarities exist
between the Bridgetown Formation and the age related Grootderm Formation of the
Marmora Terrane (Gariep Supergroup) which is considered to represent ophiolitic
material. The Bridgetown Formation probably represents segments of oceanic crust,
including seamounts of oceanic islands, which were tectonically emplaced in an
accretionary prism zone during subduction of oceanic crust underneath the Kalahari
Craton, 600 to 700 Ma ago. This resulted in the present spatial configuration of
various small greenstone bodies in the Malmesbury Group.
To date no exploitable mineral deposits have been found 1n the Bridgetown
Formation. However, Au and As anomalies in stream sediment and soil samples,
taken in the Spitskop area, require further attention. lt is suggested that the gold
and arsenic is hosted in brittle deformed clear to milky quartz veins which developed
at zones of competency contrasts in all the li tholog ies in the Spitskop area. / AFRIKAANSE OPSOMMING: 'n Aantal klein groenskisliggame van die Bridgetown Formasie is blootgestel as
verlengde lense en gange binne metasedimente van die Malmesbury Groep in die
Wes-Kaap Provinsie, Suid-Afrika. Die Malmesbury Groep is deel van die
Neoproterozo·iese tot Kambriese (Namibiese) Saldania Subprovinsie wat die
suidelike voortsetting is van 'n Pan-Afrikaanse mobiele gordel sisteem.
'n Gedetaileerde geologiese en geochemiese studie is gedoen op die grootste
dagsoom van die Bridgetown Formasie, gelee 20km oos van die dorp Moorreesburg.
Die Bridgetown Formasie bestaan uit 'n metavulkanies-sedimentere opeenvolging
wat pol ifase vervorming en metamorfisme tot en met die laer groenskis fasies
ondergaan het. Die Bridgetown Formasie word hier in die Boland tektoniese domein
ingedeel deur die Piketberg-Wellington verskuiwingsone 5km wes van Heuningberg,
subparallel a an die Bergrivier, te plaas. Dit stem ooreen met Rabie ( 197 4) se
oorspronkl ike verdeling van die tektoniese domeine.
Die Bridgetown Formasie bestaan uit: i) 'n Basale eenheid wat hoofsaaklik bestaan
uit min gedifferens ieerde alkali-metabasalte met binneplaat tektonomagmatiese
eienskappe. ii) 'n lntermediere eenheid wat bestaan uit min gedifferensieerde
tholeiitiese metabasalt en 'n jonger intrusiewe tholeiitiese metabasiet wat 'n lae
graad van differensias ie ondergaan het. Beide intermediere eenhede het
oseaanvloer-basalt (P-t ipe MORB) en eilandboog basaltiese eienskappe. iii) 'n
Boonste eenheid wat bestaan uit min gedifferensieerde asook meer
gedifferensieerde alkal i-metabasalte, tussengelaagd met metatuf met 'n alka libasaltiese
samestelling; metasedimentere gesteentes met 'n mariene oorsprong, en
grafitiese ski ste en kwarts-muskoviet skiste, beide met 'n kontinentale kors
oorsprong . iv) 'n Oorliggende metasedimentere opeenvolging wat dolomiet,
massiewe en ooli tiese chert, jaspis en jaspiliet insluit.
Die Bridgetown Formasie slu it moontlik ook 'n onderliggende gemetamorfiseerde
ultramafiese eenheid in; aangedui deur die assosiasie van Ni- en Cr-ryke
ta lkl iggame, Ni- en Cr-ryke gebande chert, chlorietskis en klein dolomiet-talk-chloriet
liggame by Spitskop, gelee direk noordwes van die hoof groensteenliggaam.
Die opeenvolg ing van magmatisme en die geochemie van die metavulkaniese
gesteentes stem ooreen met Hawaiiese vulkanisme, naamlik 'n diepwater stadium, gekarakteriseer deur alkaliese magmatisme, gevolg deur 'n hoof tholeiitiese
opbouing en post-kaldera alkaliese magmatisme. Die post-kaldera alkaliese
magmatisme het gelyktydig plaasgevind met afsetting van sedimente en chemiese
presipitate (karbonate en cherte ).
Die Bridgetown metavulkaniese gesteentes het geen magmatiese assosiasie met
6f die Bloubergstrand vulkaniese gesteentes 6f mafiese en intermediere plutoniese
gesteentes in die Malmesbury Groep nie. Fisiese en geochemiese ooreenkomste
bestaan egter tussen die Bridgetown Formasie en die Grootderm Formasie van die
Marmora Terrein (Gariep Supergroep) wat beskou word as ofiolitiese materiaal. Die
Bridgetown Formasie verteenwoordig moontlik segmente van oseaankors,
insluitende oseaan-eilande, wat tektonies in 'n melange sone ingeplaas is tydens
subduksie van oseaankors onder die Kalahari Kraton in (600 tot 700 Mj gelede). Dit
verklaar die huidige ruimte like verspreiding van verske ie klein groensteenliggame in
die Malmesbury Groep.
Tot en met hede is geen ontginbare mineraalafsettings in die Bridgetown Formasie
ontdek nie. Au en As anomalie in stroomsediment- en grondmonsters, geneem in
die Spitskop area, behoort egter verdere aandag te geniet. Daar is voorgestel dat
die goud en arseen voorkom in brosvervormde helder tot melkerige kwartsare wat
ontwikkel het in swak sones in al die litologie in die Spitskop area.
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n Ondersoek na die arbeidsprobleme vir wynboere in Wes-KaaplandLouw, P. G. (Pieter Gerhardus) January 1969 (has links)
Thesis (MCom)--Stellenbosch University, 1969. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming
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Insect macroecological patterns along an altitudinal gradient : the Greater Cederberg Biodiversity CorridorBotes, Antoinette 04 1900 (has links)
Dissertation (PhD)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: The central goal in macroecology is to determine species diversity patterns across ecological
gradients. Altitudinal and latitudinal patterns in species richness are often assumed to be
analogous. Furthermore, the primary mechanisms underlying richness patterns along these
two gradients might be similar. To date, few studies have tested whether the hypotheses
proposed to explain latitudinal richness variation apply to patterns across altitude. This study
therefore tests several hypotheses proposed to explain patterns in species diversity (i.e.
ambient energy, productivity, area and geometric constraints) and their underlying
mechanisms using altitudinal gradients in epigaeic ant and beetle species richness in the
Greater Cederberg Biodiversity Corridor (GCBC) (Western Cape, South Africa). The study
was conducted across an altitudinal gradient that was laid out from sea level to the top of a
mountain (approximately 2000 m above sea level) and down the other side thereof. First, it
was determined how the ant and beetle assemblages differ between the main vegetation types
included in the transect and which environmental variables might underlie these differences.
Thereafter, the variation in species richness and range size patterns of the two groups was
investigated across the full altitudinal gradient. This is the first study that tests the
applicability of two mid-domain models across such an altitudinal gradient using both
complete and partial assessments. The models explained large proportions of the variance in
range sizes across three domains but the ranges could have been constrained to show peaks in
the middle of the domains due to the way in which the boundaries of the domains were
selected. By contrast, the mid-domain models were not important in explaining species
richness patterns, which suggests that they cannot explain diversity across the gradient. The
species richness patterns of the two groups did not show the predicted mid-altitudinal peak.
Moreover, it was demonstrated that different processes structure ant and tenebrionid
assemblages across the same altitudinal transect. Ant species diversity was highly correlated
to contemporary climatic variables, while historical factors appear to play a more important
role in structuring tenebrionid beetle assemblages. Furthermore, support was found for the
species energy theory in the ant assemblages, as well as for two of its underlying mechanisms,
namely the more individuals hypothesis and the niche position mechanism. These results
suggest that there are likely to be substantial and complex changes to ant assemblages under
the predicted climate change scenarios for the region. Given the crucial role played by this
group in ecosystem functioning (e.g. myrmecochory) it is suggested that these responses are not likely to be a response solely to vegetation changes, but might also precipitate vegetation
changes. This study also forms the basis of a long-term monitoring programme to establish
baseline data for the epigaeic ants and tenebrionids and to monitor changes in these
communities due to climate change. / AFRIKAANSE OPSOMMING: Een van die sentrale idees in makro-ekologie is om die patrone in spesies diversiteit oor
ekologiese gradiënte te ondersoek. Verder word daar aangeneem dat spesie rykheidspatrone
oor hoogte- en breedtegradiënte analoog is aan mekaar en dat die primêre onderliggende
meganismes van die patrone dieselfde kan wees oor hierdie twee gradiënte. Tot dusver het
min studies getoets of die voorgestelde hipoteses wat breedtegradiënte in spesie rykheid
verduidelik van toepassing is op hoogtegradiënte. Hierdie studie toets dus verskeie van
hierdie hipoteses (aanvoelbare temperatuur, produktiwiteit, area en geometriese beperkinge)
en hulle onderliggende meganismes in mier en kewer spesie rykheid in die Groter Cederberg
Biodiversiteits Korridor (GCBK) (Wes Kaap, Suid Afrika). Die studie is uitgevoer oor ‘n
hoogtegradiënt wat vanaf see vlak tot ongeveer 2000 meter bo seevlak en weer aan die ander
kant van die berg af uitgelê is. Eerstens is daar bepaal hoe die mier en kewer diversiteit
verskil tussen die hoof planttipes wat oor die hoogtegradiënt voorgekom het en watter
omgewingsveranderlikes daarvoor verantwoordelik is. Daarna is die variasie in spesie rykheid
en area van verspreiding van die twee groepe ondersoek oor die hele hoogtegradiënt. Hierdie
is die eerste studie wat die toepaslikheid van twee mid-domein modelle oor so ‘n
hoogtegradiënt toets met behulp van volledige en gedeeltelike ondersoeke. Die modelle het
baie van die variasie in area van verspreiding verduidelik oor drie domeine maar die areas van
verspreiding kon beperk gewees het om pieke in die middel van die domeine te vorm as
gevolg van die manier waarop die grense van die domeine gekies is. In teenstelling, het die
modelle nie spesie rykheid verduidelik nie en dus kan hulle nie spesie diversiteit oor hierdie
gradiënt verduidelik nie. Die spesie rykheidspatrone van die twee groepe het nie die verwagte
piek by midhoogte gewys nie. Verder het verskillende prosesse mier en kewer groeperings
oor die hoogtegradiënt gestruktureer. Mier diversiteit was hoogs gekorroleer met
kontemporêre klimaatsveranderlikes, terwyl historiese faktore belangriker was vir die kewers.
Die spesie-energie teorie was ondersteun deur die data, asook die meer individue hipotese en
die nis posisie meganisme. Hierdie resultaat dui daarop dat daar moontlik komplekse
veranderinge in mier groeperings gaan plaasvind soos die klimaat verander. Miere vervul
belangrike ekologiese prosesse in ekosisteme, wat beteken dat die laasgenoemde verandering
nie bloot net gaan plaasvind as gevolg van veranderinge in die plantegroei nie, maar dat hulle
self ook veranderinge kan veroorsaak. Hierdie studie vorm ook die basis van ‘n langtermyn
moniteringsprogram om basislyn data vir hierdie twee ekologies belangrike groepe vas te stel en om veranderinge wat in hierdie gemeenskappe plaasvind, as gevolg van
klimaatsverandering, te monitor.
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Institutional overlaps in water management in the Eerste River Catchment.Nleya, Ndodana January 2005 (has links)
In this minithesis I have investigated overlapping mandates as a source of management failure in water management in South Africa in general and Eerste River Catchment in particular. I analysed major legislation which deals with water management to find out how duties and responsibilities are apportioned in the various pieces of legislation. I also undertook an exercise of evaluating roles and responsibilities played by various organs of state in water management from national government, Provincial Government of the Western Cape through to local government, in this case the Municipality of Stellenbosch and the City of Cape Town. It emerged that there were a number of areas of overlap, ambiguously defined mandates, conflict and that these were impeding on decision making in water management. In order to test the framework built above, I then applied it in the Plankenbrug River, a tributary of the Eerste River. Through analysis of newspaper clippings over a period of 4 years I was able to reconstruct conflict over ill-defined mandates in the various aspects of the management of the catchment which showed that<br />
there were differences in roles of the different state organs operating in the catchment. Water management conflict emanated from lack of congruence in the various legislation and differences in the interpretation of legislation. The various state organs seem to be aware of the constitutional duty of cooperative government that engenders state organs to work co-operatively in order to meet their developmental mandates. It seems however that the state organs were merely interested to be seen to be in conformity with this duty more than actually solving the issue as this was seen as something to be tackled at a higher level.
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A pilot emperical investigation into student perceptions of service quality at the Department of Management of the University of the Western Cape.Combrinck, Theodore Peter January 2006 (has links)
This pilot research survey was undertaken as a result of the need to assess the service quality within Higher Education in general and the Department of Management at UWC in particular. This report focuses on the complexities of measuring service quality in higher education. The quality of service delivery within education is becoming more important as the competition for students increases.<br />
The literature was searched to find a suitable measure with a sound theoretical structure. This measure was then adapted for the department.<br />
<br />
In a preliminary way this instrument was then applied to students in the department and initial results are reported on.<br />
The results revealed that undergraduates overall were uncertain in their attitude to the service quality in the department. On the other hand, postgraduate students tended to rate the service quality rather more negatively (p < / 0.004). Furthermore there were no gender differences except for tangibles (p = 000.5).<br />
<br />
This pilot study could serve as a pilot study of the service quality in an academic environment. It is the main contention of this report that students themselves should be part of defining quality.
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