The medicinal chemistry of the isomers of the cyclic dipeptide: cyclo(Trp-Pro)
- Authors: Jamie, Hajierah
- Date: 2002
- Subjects: Pharmaceutical chemistry , Cyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
- Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
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- Date Issued: 2002
De-scribing the Timaeus: a transgression of the (phal) logocentric convention that discourse has only one form, language
- Authors: Ord, Jennifer
- Date: 2002
- Subjects: Discourse analysis , Art -- Philosophy
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10763 , http://hdl.handle.net/10948/115 , Discourse analysis , Art -- Philosophy
- Description: Like writing, art making is primarily a means of human expression, a means of communication – both “allow us to categorize our (inner and outer) environment as represented by symbols” (Appignanesi, 1999: 7). Yet it is language in the traditional Western garb of rational, philosophical discourse that has been perceived as the primary means of manifesting knowledge and positing truth, not only regarding the character of human existence, but also the nature of art. This infers the acceptance of both works as literally “truth of things”, and of “a language of reason” that “perfectly represents the real world” (Appignanesi, 1999: 77). Going against the grain of this traditional bias, Jacques Derrida holds that, firstly, “human knowledge is not as controllable or as cogent as Western thinkers would have it”: secondly, that language functions in “subtle and often contradictory ways” thus rendering certainty, truth, and perfect representation ever elusive to us (Lye, 1997: 2); and, thirdly, that “practices of interpretation which include art but are not limited to language, are extended discourses” (Appignanesi, 1999: 79). So, the “work of reason” (or rationalism) in this sense, is no longer the definitive “voice” of authority when it comes to ascribing meaning, proclaiming a message, defining truth, etc. Having the grip of its authority loosened and thus its rigid, imposing borders opened up, the communication of knowledge as a form of “aesthetic fiction” (Megill, 1987: 265) is allowed entry into the rarefied field of philosophical discourse. Moreover, if visual art (one such “aesthetic fiction”) is a process of sign-making, as is written and spoken language; if it therefore constitutes a signifying system, as does written and spoken language (Bal and Bryson in Preziosi, 1998: 242); and, if art is not just about autonomous, in-house formalism, then can it not, in any case, validly offer a form for discourse, albeit a different kind of discourse, a discourse that is not “truth seeking” (Sim, 1992: 33)? Here, the maker of the proposed artwork-asdiscourse would not be attempting to establish the truth or falsity of a philosophical position, but, as Derrida would have it, create a form which, without mimicry, would evocatively allude to Plato, his “deconstructor” and the maker of the proposed artwork. Discourse in this sense, then, would generate “active interpretation… infinite free association” (Megill, 1987: 283), because, as in Derrida’s writing, interpretation no longer aims at “the reconciliation or unification of warring truths (Sim, 1992: 10); in other words, it breaks with the (phal)logocentric tradition of discourse as dialectical and becomes questioning without closure. For visual art to enter the exalted arena of philosophical discourse, it cannot be selfreflexive in the Greenbergian or formalist sense – it has to be about something philosophical and this ‘something’ will be a deconstructive response to Plato’s doctrine of the two worlds in the Timaeus. What I propose presenting, then, is an imagographic rather than (phal)logocentric exposition of philosophical content where the aim is not to shape a certainty or to infer an absolute presence or essence of anything, but rather to suggest traces of the maker of the artwork reading Derrida, reading Plato. The proposed artwork as a response to texts will thus be a “pre-text” of my own endeavour.
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- Date Issued: 2002
Modelling the broiler performance under small-scales and semi commercial management condition
- Authors: Prince, Siliga Hulisani
- Date: 2002
- Subjects: Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10963 , http://hdl.handle.net/10948/110 , Broilers (Chickens)
- Description: Introduction : World poultry meat consumption consists of three major segments: broilers, turkeys, and other poultry which includes spent egg layers, spent breeder hens/males, ducks, geese, guinea-fowl, pheasants, quail, ratites, ostriches and emus. Broilers clearly dominate the world poultry consumption contributing about 70 percent to the world poultry market. Turkeys account for about eight percent while other poultry provides the balance of 22 percent (Roenick, 1998). The world broiler industry has been, and continues to be a very dynamic industry. It has been typified with unprecedented growth in terms of production. In 1961, the world produced 6.5 billion broilers. By 1990, the total annual production was a little over 27 billion broilers and by 1996, total world production had grown to 35.3 billion (Van der Sluis., 1999). This represents a fivefold increase in 35 years, and it has not stopped growing since, with world production surpassed 38 billion in 1998 (Van der Sluis., 1999). In Africa the human population was estimated to be 819.9 million, while the total poultry population of the continent was estimated as 1.133 million chickens, 15 million ducks and seven million turkeys in 1998. Production scale being 1.781701 metric tones (MT) of hen eggs, 2.269000 MT of chickens’ meat, 32.824MT of turkey meat and 52.989MT of duck meat (Gueye, 2000). Commercial poultry products are also imported and exported. For example, 12.000 metric tons of poultry meat was estimated to have been exported from South Africa in 1999, whereas 87.000 and 10.000 metric tons of poultry meat was imported into South Africa and Egypt, respectively (Gueye, 2000). In South Africa poultry production is moving toward the 21st century with the potential for increased development being greater than any other sector of the agricultural industry. The small-scale to medium-scale or semi-commercial farmer is becoming a role-player that needs to be serviced by the poultry industry (Fourie, 2000). The industry will have to take up the challenges that are facing an entrepreneur starting with a poultry venture. The poultry industry has developed from a humble beginning at the turn of the century into a multi-million Rand enterprise where protein is provided through the commercial and small marketing sector (Fourie, 2000). Some of the larger commercial companies market three million birds per week. It is estimated that the commercial company sector is responsible for 75 to 85 percent of production and marketing of white meat in this country whereas the small-scale and medium-scale or semi commercial poultry production enterprises provide 20 to 25 percent of the white meat through the sales of slaughtered and live poultry sale to rural, peri-urban and urban settlements (Fourie., 2000). Small-scale and semi-commercial broiler production is developed by entrepreneurs who buy day-old chicks from the big commercial hatcheries, rear them to the age of five to eight weeks and sell them through a marketing network or small outlets. The small-scale consist of farmers who reared 100 t0 1000 chickens per batch and semi-commercial consist of farmers who reared 1000 to 5000 chickens per batch. These types of farmers acquire very little technical backup in terms of a training and services center where assistance is available every day of the week. The broiler industry requires birds that are of commercial crosses selected for their ability to grow very fast and produce a good quality carcass in the shortest time frame. The small farmers purchase broiler stock, as the day-old chicks from commercial hatcheries and reared them up to six to eight weeks before slaughtered or sold as live chickens. The selling of live chickens through a network outlets system is becoming an industry that is growing at a steady pace, as household food security is becoming important to communities (Fourie, 2000). The price of feed is the single most expensive item on the list of expenses of a farmer because of their financial constraints. The small-scale and semicommercial broiler farmer is faced with the problem of buying small quantities of feed at an inflated price. The problem can be alleviated by groups of small farmers joining co-operative and buying feeds in bulk from suppliers and redistributing to small farmers. The community co-operative can once again play a major role in the distribution of small amounts of feed to its member. The biggest challenge is to provide training with a “hands on” approach. It will be ideal to have a training center where small farmers can be trained in all aspects of poultry production. The training facility will have to operate as a fully operational poultry unit with no risks to bio-security of a commercial enterprise. Training will have to be provided in aspects like hatchery, housing, broilers and record management depending on the farmer’s needs. There is also a need for the research on broiler performance under small-scale and semi commercial farming. Research in this sector of poultry production should look in appropriate feeds, feeding, technology, genotype and performance of genotypes under the system. Emphasis in this study will be on growth patterns and performance of the Ross hybrids as a modern broiler under small-scale and semi commercial management condition. Aspect of the environment such as age, type of feeds and feeding methods, housing, seasons, lighting and genotype will be taken into consideration. The result of the study will provide a realistic database for mathematical modeling of production response and guideline for management planning in small-scale and semi-commercial management condition. Also this result will be important to broiler breeders, to determine the suitability of the modern broiler to small-scale and semi commercial management conditions. The objective of the study was to evaluate the mathematical model that could describe the performance of broilers under the small-scale and semi-commercial management conditions.
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- Date Issued: 2002
Vergelyking van Tilapia (Oreochromis Mossambicus)en Koi (Ciprinus Carpio) in verskillende produksiestelsels
- Authors: Van der Merwe, Johan Philip
- Date: 2002
- Subjects: Fish culture
- Language: Afrikaans
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10967 , http://hdl.handle.net/10948/114 , Fish culture
- Description: Die studie was uitgevoer om te bepaal of warmwaterspesies soos tilapia (Oreochromis mossambicus) en koi (Ciprinus carpio) gebruik kan word as deel van 'n roterende akwakultuur produksie sisteem in die Wes-Kaap. Drie produksiestelsels (drywende hokstelsel; gronddamme en hersirkuleringseenheid) was ge-evalueer vir beide tilapia en koi produksie. Twee verskillende diëte (tilapia, 32% proteien, 'n lae waarde dieet en koi, 32% proteien, 'n hoë waarde dieet) was ook ge-evalueer vir die effek op koi produksie. Tilapia- en koi vingerlinge was teen dieselfde lading (250/hok) in elke produksiestelsel geplaas. By die begin van die proewe het die tilapia vingerlinge 'n gemiddelde gewig van 60-80g en die koi vingerlinge 'n gemiddelde lengte van 30-40 mm gehad. Die visse is twee keer per dag gevoer en data is op 'n maandelikse basis oor 'n periode van 84 dae versamel. Produksie data vir die tilapia versamel was: 1) die gemiddelde daaglikse toename, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die produksie data versamel vir koi wat twee verskillende diëte ontvang het in drie verskillende produksiestelsels was: 1) die gemiddelde daaglikse toename in lengte, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die resultate van die tilapia studie het aangedui dat tilapia in die hersirkuleeringseenheid het deurgaans 'n swaarder gewig gehad (p<0.05) as die van die drywende hokstelsel en gronddam stelsel. Terwyl die gronddam stelsel weer 'n swaarder gewig gehad het as die drywende hokstelsel behalwe vir April (171,67 / 39,49 vs 159,33 / 22,15). Nieteenstaande die verskil in begin gewig en eind gewig in die guns van die tilapia in die hersirkuleringseenheid teenoor die ander twee stelsels het die GDT tussen die drywende hokstelsel en die hersirkuleringseenheid nie noemenswaardig verskil nie (1,20 / 0,15 vs 1,40 / 0,24). Die tilapia in die gronddamme het egter swakker (p<0,05) gewigstoename van 0,72 / 0,32 g gehad teenoor die tilapia in die drywende hokstesel 1,40 / 0,24 g en 1,20 / 0,15 g van die tilapia in die hersirkuleringseenheid. Tilapia in die gronddamme het dus ongeveer 45% swakker gemiddelde gewigstoename getoon as die van die drywende hokstelsel en hersirkuleringseenheid. Die produksiestelsel het 'n hoogs betekenisvolle invloed (p<0,001) op die groeipotensiaal van tilapia gehad in hierdie studie. Die gemiddelde totale hoeveelheid voer verbruik was nie statisties verskillend tussen die drywende hokstelsel en gronddam stelsel nie (29,83 / 2,66 vs 30,83 / 5,42), maar wel (p<0,05) vir die hersirkuleringseenheid (29,94 / 0,88). Die VOV het nie verskil tussen die drywende hokstelsel en hersirkuleringeenheid, maar daar was wel 'n verskil (p<0,05) tussen hierdie twee stelsels en die van die gronddamme. Die totale gemiddelde mortaliteite van tilapia was die hoogste (p<0,05) vir die drywende hokstelsel in vergelyking met die gronddamme en hersirkuleringseenheid. Die drywende hokstelsel het 14,67 / 14,61% meer mortaliteite gehad as die gronddamme en hersirkuleringeenheid. Die koi studie se resultate dui aan dat die tipe stelsel het 'n hoogs betekenisvolle (p<0,001) invloed gehad op die gemiddelde toename in lengte van die koi vis vir die somerseisoen. Die tipe dieet het geen invloed op die toename in lengte van koi vis vir al drie die stelsels ge-evalueer, maar die interaksie tussen dieet en die tipe stelsel was wel betekenisvol (p<0.05). Die interaksie tussen die tipe dieet en die tipe stelsel was die hoogste vir die groddamme 136,41 / 32,46 mm en 136,25 / 33,08 mm vir beide tilapia en die koi diëte gevoer. Die gemiddelde totale voer wat deur koi visse in die drie stelsels verbruik is, het wel statisties van mekaar verskil (p<0,05). Koi visse in die gronddam stelsel het meer voer verbruik vir beide die tilapia- en koi dieet (31,03 / 2,01 en 29,67 / 3,57) in vergelyking met die (26,35 / 2,44 ; 26,98 / 0,49 en 5,50 # 0,52 en 6,13 / 0,22) vir die drywende hokke en hersirkuleringseenheid stelsels onderskiedelik. Die % mortaliteite was betekenisvol (p<0,05) vir die verskillende stelsels. Koi visse in die hersirkuleringseenheid het die hoogste mortaliteite gehad vir beide die tilapia en die koi diëte (65,50 / 18,07% en 79,50 / 38,27%) terwyl koi visse in die gronddamme die laagste mortaliteite ondervind het (1,20 / 1,20% en 2,33 / 4,89%) vir beide die tilapia en koi diëte. Die koi in die gronddam stelsel het die beste resultate gelewer en dit is ook moontlik om koi 'n lae waarde dieet te voer sonder nadelige effekte op produksie.
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- Date Issued: 2002
The relationship between the leadership, internal quality, and customer satisfaction levels of dealerships in a South African motor vehicle organisation
- Authors: Botha, Jennifer
- Date: 2002
- Subjects: Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1185 , http://hdl.handle.net/10962/d1002802 , Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
- Description: This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected.
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- Date Issued: 2002
Participation and dialogue in development
- Authors: Neves, David Telles
- Date: 2002
- Subjects: Action theory , Communication in economic development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3148 , http://hdl.handle.net/10962/d1007456 , Action theory , Communication in economic development
- Description: "Participation" is a frequently articulated requirement within the context of community development. Yet despite this, the concept of participation is neither comprehensively theorised, nor entirely unproblematic. The theoretical paucity surrounding participation is particularly marked within accounts of its interactional and relational dynamics . This thesis is accordingly concerned with theorising the interactional and relational features of participation in, and for, development. To this end a small development intervention, constituted as an agricultural co-operative within a rural area of South Africa, is examined. In this inquiry the phenomenon of participation is viewed through the lens of dialogical-activity. This enables explication of the "joint activity" directed towards participatory development, within the focal research setting. The overarching theoretical framework for this thesis is conferred by Activity theory. Orientated towards examining the collective and artefactually mediated nature of human action, Activity theory is foregrounded in Y. Engeström's (1989; 1999b) analytic schema of the Activity System. This Activity System framework is expanded by the inclusion of communicative and semiotic elements; an inclusion effected by reference to R. Engeström's theory of communicative action (1995,1999), which in turn, draws on theoretical precepts gleaned from the work of Mikhail Bakhtin. The resultant fusing of dialogue and activity therefore serves to extend Activity theoretical insights. The results of this research are based on data collected from a multitude of sources within the focal participatory development research setting, including internal project documentation, interview transcripts and field notes. The dialogical Bakhtin-derived an alytic categories of speech genre , voice and social language were drawn on in order to examine this textual data , and to explicate the interactional and relational features of participatory development. Analysis of these served to reveal the polyphony of (speech genre constituted) voices, wherein the phenomenon of participation is disparately accentuated. The results chapter moreover discusses the substantial mismatches and discontinuities in the referential object invoked by the various roleplayers, within the focal research context. This thesis considers the sources of these discontinuities and tensions, including how they point to historically constituted contradictions within participatory development. It furthermore briefly examines the opportunities and affordances these offer up for expansive new forms of activity. Finally, in re-examining participation and development, the complex, and sometimes antithetic relationship that exists between these two concepts and their associated social practices, are considered.
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- Date Issued: 2002
Nearest-neighbour analysis and the prevelance of woody plant competition in South African savannas
- Authors: Shackleton, Charlie M
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181640 , vital:43754 , xlink:href="https://doi.org/10.1023/A:1014795505362"
- Description: Inter- and intra-specific competition has long been regarded as a significant determinant of the structure and function of woody plant communities in African savannas. The most widely used approach to detect the presence or absence of competition has been the use of nearest-neighbour methods. Although several studies have been published reporting the presence of competition in Acacia dominated communities, less than 20 plots have been sampled across all these studies. Results from broad-leaved communities are variable, and also based on a small sample number. Consequently, this study sought to assess the prevalence of competition from a large number of savanna sites (45), and to identify abiotic and biotic factors characterising sites with competition relative to those without. Using the nearest-neighbour method only four sites (9.3%) indicated the presence of inter-specific competition; two were Acacia dominated communities (18.2% of Acacia sites) and two were broad-leaved communities (7.7%). These four sites had a significantly higher mean annual rainfall and fewer woody species than sites without inter-specific competition. There were also significant relationships between the inter-specific competition index and the dominance index and the number of species at a site. In terms of intra-specific competition only ten of the 31 sites tested revealed a significant correlation between nearest-neighbour distance and summed canopy volume of the two neighbours. Seven were for Acacia species (55.6% of the Acacia species comparisons) and three were for broad-leaved species (21.4% of the broad-leaved species comparisons). Sites lacking evidence of intra-specific competition were at a significantly lower slope position and had a smaller proportion of small stems. The lower prevalence of competition in South African savannas detected in this study using the same method as previous studies is discussed, and the appropriateness of nearest-neighbour analysis is examined.
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- Date Issued: 2002
Imaging the metaphysical in contemporary art practice : a comparative study of intertextuality, poststructuralism and metaphysical symbolism
- Authors: Opperman, J. A.
- Date: 2002
- Subjects: Mind and body , Metaphysics in art
- Language: English
- Type: Thesis , Masters , MTech (Fine Art, Painting)
- Identifier: vital:10762 , http://hdl.handle.net/10948/101 , Mind and body , Metaphysics in art
- Description: It was then that I decided to investigate how contemporary forms of metaphysical imaging have evolved formally and stylistically. I began to question how such approaches might be informed by current philosophical thought, given that many contemporary theorists have adopted a sceptical view towards metaphysical discourse. This point of contention presented me with the initial challenge of finding an artist whose exploration of metaphysical content is supported by topical philosophical thought. I intended this inquiry to serve as a basis from which to develop my own approach to imaging metaphysical content and to situate it within the context of contemporary thought.
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- Date Issued: 2002
Secretariate report - Mobilise and invest for a sustainable cadre development
- Authors: NUM
- Date: 2002
- Subjects: NUM
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/149517 , vital:38860
- Description: Three years ago this Province under the banner of the Western Cape National Union of Mineworkers gathered in this constitutional structure, the Regional conference under the slogan “Develop Leadership to Advance Socialism”. That conference then declared and adopted a comprehensive programme of action to take forward that Regional conference declaration. That the regional committee should and within the broad framework of the declaration ensure that the NUM in a regional context fight for better working conditions of our members. That the RC develops concrete programmes for the broader structures and membership to understand and ultimately be implemented at those levels. This conference has to deal with the assessment of the progress made during this period under review. Within the context of contestation forward mobility is ensured that seeks to help build the working class leadership which is ultimately or essentially political leadership. Worker control is one of the key founding principles of our union which will be better understood and implemented when we are to begin to find synergy between the worker leadership and the intellectual capacity within our organisation. This report will deal with the different chapters as identified. This report will also deal with our participation in COSATU structures as well as lack of cohesiveness between branch leaders and general membership and also the possible fear to engage. We will also try and attempt to discuss the lack of information flow from our structures to the broader membership. As we engage this report, let us try to use our organisational tools to resolve the problems facing our region and in particular the branches and as a result find suitable solutions to build and strengthen the organisation.
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- Date Issued: 2002
Cyclic voltammetric studies of octabutylthiophthalo-cyaninato-cobalt (II) and its self-assembled monolayer (SAM) on gold electrode
- Authors: Ozoemena, Kenneth , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289567 , vital:56650 , xlink:href="https://doi.org/10.1142/S1088424602000130"
- Description: The synthesis of thiol-derivatized cobalt phthalocyanine complex, 2,3,9,10,16,17,23,24-octa (butylthiophthalocyaninatocobalt(II) (CoOBTPc) is described. Cyclic voltammetric data of this complex in DMF showed five quasi-reversible and reversible, diffusion-controlled redox couples, comprising both the phthalocyanine ring and central metal redox processes. The CoOBTPc complex forms a self-assembled monolayer (SAM) on gold electrode. The investigation of the integrity of this SAM, using the established cyclic voltammetric methods in aqueous alkaline solutions, gave evidence about the formation of a stable and easily reproducible monolayer. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor in alkaline pH is limited to a potential window of between −0.20 and +0.55 V vs Ag/AgCl.
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- Date Issued: 2002
Process for the preparation of vanillin from a mixed m-cresol/p-cresol stream
- Authors: Buddoo, Subash
- Date: 2002
- Subjects: Vanillin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10968 , http://hdl.handle.net/10948/138 , Vanillin
- Description: The Vanillin project was undertaken by AECI as it was believed that with the raw materials available from SASOL i.e. cresols, it would be possible to develop a process that would be globally competitive. A process for preparing both vanillin and ethyl vanillin was developed by AECI’s Research and Development Department using a mixed m- and p-cresol stream as feed. The displacement of bromide by methoxide is very successful when using a dimethyl formamide (DMF)/alcohol solvent system and excellent conversions (>95%) and selectivities (>95%) may be obtained. However, the use of DMF, which poses a serious chronic health risk, is unacceptable in this process since the products are intended for use as food and flavouring chemicals. In view of the above the main objectives of this study were: · To find a suitable alternative solvent system, which could produce comparable results while still being economically viable; · To develop an appropriate experimental protocol in the laboratory based on the alternative solvent system; · To determine the important reaction variables by conducting statistically designed experiments; · To optimise the reaction to produce a reproducible and robust experimental protocol; and · To test the reaction thoroughly at bench-scale level and to obtain experimental data for scale-up to pilot plant The most promising alternative solvent system was a methanol/methyl acetate mixture, which produced satisfactory results in the preliminary assessment (conversion of 98.3% and selectivity of 92.0%). DMA and acetonitrile also produced promising results but were not considered for further investigation because of toxicity and cost issues. A set of statistically designed experiments was carried out on the methanol/methyl acetate solvent system where four variables were tested i.e., substrate concentration, temperature, catalyst loading, and methanol to methyl acetate volume ratio. The experimentally determined response surface model showed that the most important variable was catalyst loading (63.2%) for conversion. With respect to selectivity, the most important variables were catalyst loading (31.9%) and methanol to methyl acetate ratio (33.1%). The optimum reaction conditions were as follows: · Temperature: 120°C · Methanol:methyl acetate: 15:1 vol/vol · Catalyst loading: 8 mol % to substrate · Substrate concentration: 22 %m/m on solvent · Catalyst: Copper(I) bromide · Sodium Equivalents: 2.7 wrt substrate · Time: 3 hours The optimum conditions were tested for reproducibility in a 1 Labmax pressure reactor. Replicated reactions, two at a 10% and two at a 20% substrate concentration gave conversions and selectivities all greater than 90%. Although the reaction mixture was a slurry at these concentrations, the reactions were very fast and virtually complete within the first hour (~95% conversion). Initial scale-up studies were conducted in an 8 Parr reactor where five reactions were carried out using the optimum conditions described above. The conversion of substrate and vanillin selectivity was consistently high and compared favourably to the Labmax reactions. The average conversion was 97.3% (96.3 to 98.5%) at an average selectivity of 98.2% (97.4 to 99.1%). A study of the reaction kinetics confirmed that the reaction was first order with respect to the substrate as a plot of substrate concentration versus reaction rate gave a straight line. The rate constant was calculated as 1.1096 k(h-1). The reaction mechanism proposed for the copper assisted nucleophilic aromatic substitution involves the formation of an adduct between sodium methoxide, methyl acetate and copper(I) bromide. The formation of a transient intermediate with the substrate allows intramolecular delivery of the methoxide ion to the aryl moiety through a CuI – CuIII type cycle.
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- Date Issued: 2002
An assessment of the impact of the black village communities, their associated land-use and related practices on water quality of the Kat River in the Eastern Cape, South Africa
- Authors: Soviti, Malixole Knottien
- Date: 2002 , 2013-05-16
- Subjects: Water quality -- South Africa -- Kat River , Water -- Pollution -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4810 , http://hdl.handle.net/10962/d1004638 , Water quality -- South Africa -- Kat River , Water -- Pollution -- South Africa -- Eastern Cape
- Description: Amongst others, the South African National Water Act No. 36 of 1998 acknowledges that access to sufficient safe and clean water is a basic right to all South Africans. However, it is well known that millions of inhabitants of rural communities in South Africa are still deprived of this right. Many rural communities in South Africa are thus consuming unsafe, untreated water everyday, thereby exposing themselves to waterborne diseases. The main reason of concern however is the fact that, nevertheless, little is known about rural water quality in South Africa as most water quality work is being undertaken in urban areas. The study's aim is twofold: first, the study examines the impact of Black rural communities' land-use and related activities on water quality and second is specifically, to study the washing practices of the rural communities in the upper Kat River area. To understand the potential impacts of the upper Kat River Black village communities and their associated land-use practices on the quality of upper Kat River catchment, prominent land-use and related activities in the area were investigated. Study area maps were studied and field surveys undertaken to observe major land-use and related activities in the area. The results of the study show that most used land in the area is being utilised for agricultural activities. Settlements and commercial forestry also occupy considerable areas of land. The literature survey suggests that such land-use could have a considerable degrading impact on the quality of both surface and groundwater. The study also investigated the impact of the in-stream use of detergents on water quality in the upper Kat River valley, Eastern Cape - South Africa. In-stream washing practices of certain communities in the upper Kat River valley were investigated and the impact of detergents on water quality was assessed. Recovery of the flow from the input of detergents was also measured. During the study, it has been ascertained that doing laundry by the stream is the common practice in the study area. Water quality analysis results show a remarkable increase on the levels of chloride, turbidity, and electrical conductivity in water as a consequence of direct input of detergents practice into the river during the washing. The recovery of the water quality at a distance of 1km from site of input was almost complete. Water quality monitoring programme was undertaken to establish a link between land-use and the quality of water. In a water quality study routine carried out for a period of 40 weeks on a twice monthly frequency, the state of the flows of the river was determined; water samples were collected at pre-determined points; and the in situ analysis of selected water quality variables (with the exception of the faecal coliforms whose analysis was carried out in the biotechnology laboratory) was carried out. Results of the study showed that the concentration of the studied water quality variables in the area varied widely with time. A clear distinction in concentration of variables such as electrical conductivity, turbidity, pH, total hardness, chloride, and nitrate was evident at the high compared to the low flow period of the study. The concentration of the studied water quality variables in the upper Kat River catchment area also seemed to vary over space. The concentration of variables such as electrical conductivity, pH, total hardness, chloride, nitrate, potassium, number of faecal coliform bacteria per 100ml was observed to be higher in most of the tributary streams than the main river. Turbidity however was orders of magnitude higher in the Kat River than the rest of the tributaries. Most importantly however, results of the study showed that there is a strong link between the quality of water and land-use and related activities in the area. The spatial results of the study showed a strong connection between some land-use and the concentrations of water quality variables. For example, areas of intense grazing were noted with high concentrations of nutrients like nitrate and a higher number of faecal coliform bacteria per 100 ml of water. It was established during the study that land-use and related activities in the upper Kat River valley are negatively impacting on the quality of water thereby rendering it less fit for use for domestic purposes. The continued use of the polluted water by the communities is thus accompanied by a danger of the outbreak of waterborne diseases like cholera. When the concerned communities met in a workshop to discuss the issue of quality of their water, they committed themselves to: • shunning water polluting activities, • at least boiling their drinking water before consuming it. The communities also requested a meeting with the Department of Water and Forestry officials to request a treated, piped supply of water. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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- Date Issued: 2002
The role of cellulases and glucohydrolases in the solubilisation of primary sewage sludge
- Authors: Ngesi, Nosisa
- Date: 2002 , 2013-05-09
- Subjects: Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4080 , http://hdl.handle.net/10962/d1007454 , Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
- Description: Biological sulph ate reduction has been identi fied as a potentially valuable process for removing sulphate and heavy metals from indllstrial effluents. The role of sulphate reducing bacteria (SRB) in this process has attracted the attention of biotechnologists and recently of enzymologists due to its fundamental properties and possible role in AMD bioremediation. These obligatory anaerobic sulphate-reducing bacteria are commonly known to dissimilate sulphate for energy. Under anaerobic conditions SRB oxidize simple organic compounds such as lactic acid with the sulphate and thereby generate hydrogen sulphide (a stTong reducing agent) and bicarbonate ions. The hydrogen sulphide in turn reacts with contaminant metals contained in AMD and precipitates them out of solution as metal sulphides. Bicarbonate ions neutralize AMD by reaction with protons to form carbon dioxide and water. Organic matter in the municipal sewage sludge has been identified as a potential source of electron donors for su lphate reduction. However, this organic matter is in the polymeric form that cannot be util ised by SRB. The latter depend on the activities of other hydrolytic bacteria for the degradation of complex polymers. Hence the availability of these monomeric substrates is a major factor, which may constrain further process development and is considered a rate-limiting step. Thi s study is therefore undertaken to investigate the bacterial glucohydrolase enzymes involved in the digestion of the polysaccharides present in the sewage sludge with specific interest in cellulases and/or p-glucosidase enzymes. The goals of the research are to: isolate, identify, purify and quantify these enzymes; study their distribution with respect to time, pH, and temperature; maximize and quantify the hydrol ys is products; study whether sulphide and sulphate have an enhancing or an inhibitory effect on the activity of enzymes; optimize the enzyme activity against substrate and/or product inhibition and soluble heavy metal salts. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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- Date Issued: 2002
The evolution of a security community through a process of integration: problems and prospects for the SADC region
- Authors: Šebek, Vita
- Date: 2002
- Subjects: Political stability -- Africa, Southern , Southern African Development Community , National security -- Africa, Southern , Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2831 , http://hdl.handle.net/10962/d1003041
- Description: This thesis examines the security problematic of African states and focuses more particularly on the SADC region. It links the security problematic with the transactionalist approach to (supra)national integration and the concept of a security community, introduced into internatIonal relations theory by Karl Deutsch and his colleagues. In relation to the (in)security of SADC member states, the thesis attempts to demonstrate that national integration of these states (i.e. the establishment of an amalgamated security community) has at least to accompany if not precede the establishment of a security community at the regional level (i.e. a pluralistic security community). Since threats to the security of SADC member states are mainly nonmilitary in nature, the 'realist' concept of security is broadened to include political, economic, societal and environmental aspects of security at different levels. Furthermore, Deutsch's concept of a security community is redefined in line with the 'new security thinking' and adapted to the situation in African states. Moreover, this thesis attempts to demonstrate that it is essential for SADC member states to become strong and socio-economically cohesive in order to improve their competitiveness in relation to developed states, especially in their ability to deal with internal and ransnational/regional threats to their security, which are (in)directly caused and perpetuated by the lack of national integration, inefficient state-making and underdevelopment - the sources of their weakness.
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- Date Issued: 2002
The impact of multi-skilling training on the paintshop production environment and its employees at Volkswagen South Africa (VWSA)
- Authors: Bhika, Chandrika
- Date: 2002
- Subjects: Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10852 , http://hdl.handle.net/10948/130 , Employees -- Training of , Automobile industry and trade -- South Africa -- Eastern Cape
- Description: Global competition and rapid technological change have been the driving forces for a more flexible and competent workforce. Continuous employee training assists organisations to achieve their goals by adding value to their key resources, the human factor. The demand for a more qualified workforce becomes a strategic force in the effort to raise competitiveness. Providing, obtaining and improving the necessary skills are important in responding to a rapidly changing international economy. Life-long learning and continuous skills development are the new requirements imposed by our knowledgeintensive society. The overall purpose of the research was to determine the impact of multi-skilling training (MST) on the paintshop production environment and its employees at Volkswagen South Africa (VWSA). The objectives of this research were to: Identify the elements of multi-skilling training and guidelines for its development and implementation; Critically evaluate the current system; Determine the impact of multi-skilling training on the production environment in the paint shop at VWSA The research methodology for this study comprised the following steps: Firstly, the development and implementation of MST at Volkswagen South Africa was assessed. The elements of MST and its impact on production and the employee worldwide were determined through the literature study. Secondly, the limitations of the current MST system used in the paintshop at Volkswagen South Africa were assessed in an empirical study, which involved completing of questionnaires. The empirical study proved that the current MST system employed in the paintshop at Volkswagen South Africa had assisted in improving production, and increasing the employees’ morale. The final step of this study entailed the formulation of recommendations, which are as follows: · Sufficient time should be allocated for practical training. · Frequent job rotation must be implement ed. · Advanced MST must be implemented after completion of Level Four. · MST should be presented in English, Afrikaans and Xhosa.
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- Date Issued: 2002
Towards a broader socio-ecological education : a case study of school based curricular reform
- Authors: Cimma, Gary Martin
- Date: 2002
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:20973 , http://hdl.handle.net/10962/5763
- Description: This work documents and analyses an action research project that the researcher undertook in conjunction with colleagues at an independent Catholic high school in Johannesburg. The main objective was to try to expand the existing curriculum in operation at the time of starting the research to one, which was more socio-ecologically sensitive. One of the key references during the action research was the recently drafted ‘Vision Statement’ document, which detailed the educational ideals of the school. Some of the key findings that emerged as the research proceeded, were that the levels of socio-ecological sensitivity displayed by the learners were influenced by the backgrounds from which they came, and that these background environments were often not comfortable with the changes taking place in the educational and greater South African environments. The Participatory Action Research mode of research which was used proved to be problematic in that only a handful of the educators actually got involved in participating in the project. The failure of many of educators to get involved was, in the opinion of the researcher, due to their lack of understanding how important the development of social and ecological sensitivity are to the necessary change capacity required in present day South African society. The need to be involved in the ongoing development of curriculum as required by Curriculum 2005 as a form of Outcomes Based Education was also problematic as some educators were not familiar with their role in this regard. The limited time-span of the research was also a limiting factor as the development of a socio-ecologically sensitive curriculum required changes in some fundamental attitudes and approaches to education and the environment.
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- Date Issued: 2002
A workers handbook on HIV and AIDS
- Authors: COSATU
- Date: 2002
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/135270 , vital:37253
- Description: AIDS is a trade union issue and must be discussed and placed on the agendas of all union meetings. We have committed ourselves to campaign for HIV prevention, care and treatment with the same determination and energy with which we fight many other working class struggles. COSATU has also committed to work in partnership with other trade unions, government, business and organs of civil society in the fight against the disease.”
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- Date Issued: 2002
Promotion of liberal values in South African foreign policy : beyond the structural imperatives of the international system?
- Authors: Mkalipi, Zanethemba
- Date: 2002
- Subjects: South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2865 , http://hdl.handle.net/10962/d1007662 , South Africa -- Foreign relations
- Description: The end of the Cold War in the early 1990s led to a multilateral international system no longer divided by contending forces of capitalism and communism. In the context of South Africa, the end of the Cold War occurred at a juncture where the apartheid government was being challenged by pro-democracy forces that have fought against it for decades. The developments in the international system and in the country led to South Africa adopting universal liberal values not only in its constitution, but also in its international relations. Foreign policy documents and statements by the ministry of Foreign Affairs also reflected the country's aspiration of becoming a mediator, a facilitator for democracy and a peacemaker especially in the context of Africa. International expectation mounted as South Africa was perceived as possessing the capacity to act in a manner that advances democratic values and which gives voice to the weak nations of the world. However, the aura of a post-apartheid South Africa that would act not only in its interest, but also in the interest of the world community never fully materialised. South Africa failed to act in a manner consistent with its stated commitment to democratic values when it recognised Peoples Republic of China, an undemocratic and repressive government. It also marched into Lesotho in 1998, resulting in the destabilisation of this tiny Southern African country. These events led to an increasing criticism of the South African government. Some argued that South Africa was still inexperienced given its recent emergence as a world player. Others blamed the inconsistency on a too broad and ambitious foreign policy that set itself for failure. This study seeks to contribute to the conceptual understanding of the debate regarding the ambiguous nature of South Africa's foreign policy behaviour. It situates the conceptualisation of South Africa's foreign policy within the predominant debates in international relations between realism, political structuralism and pluralism. Firstly, it holds that the end of the Cold War and ascendancy of globalist conceptions of international relations did not lead to the inadequacy of political structuralism as an organising framework. Secondly, it attempts to clarify the gap between South Africa's foreign policy and foreign policy behaviour by employing the assumptions advanced by political structuralism, Thirdly, a case study of South Africa's foreign policy towards China, Lesotho, the Great Lakes and Swaziland is carried out. Here it is demonstrated that the ambiguities of South Africa's foreign policy are a function of the constraints imposed by the political and economic structure of the international system, It draws its conclusion by providing methodological recommendations to South Africa's foreign policy makers and future researchers in the field of foreign policy analysis.
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- Date Issued: 2002
A comprehensive study of the social responsibility practices of two selected financial insitutions
- Authors: Grootboom, Alan Avril Douglas
- Date: 2002
- Subjects: Social responsibility of business -- South Africa , Financial institutions -- South Africa -- Social aspects
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10857 , http://hdl.handle.net/10948/80 , Social responsibility of business -- South Africa , Financial institutions -- South Africa -- Social aspects
- Description: Different forms of social responsibility practices have been prevalent in South Africa. Most of South African companies decided to bear the minimum costs when it comes to contributing to society. An improved version of social responsibility evolved since the transition in the 1990’s and South Africa’s re-integration into the global economy after lifting of economic sanctions. This came about after decades of large profit margins enjoyed by South African companies at the expense of low labour costs that led to inequalities in income distribution in South Africa. The social responsibility involvement/programmes are more or less the same across similar companies in South Africa. The reasons for business engaging in social responsibility are varied, ranging from poverty alleviation to sustainable development of society. Executives started to buy into the idea that social responsibility can be beneficial to the business and society. The changing attitudes regarding the role of business in society have made social responsibility an increasingly prominent issue over the past decades, but to decide on which projects will have a mutually beneficial impact on society and business, was one of the major challenges that companies have to face. It is against this background that the researcher investigated and compared the social responsibility practices of two selected financial institutions. The focus was on the practices of the two financial institutions in selecting targets for socially responsible involvement. This problem was supported by six secondary problems. The researcher first did a literature study to place social responsibility in perspective. The main purpose of the literature study was to identify and suggest how companies select the targets for said responsible involvement. An empirical investigation was conducted, focusing on Standard Bank and ABSA Bank. The demarcation of the study was restricted to these organisations as the assumption was made that their social responsibility practices are representative of the social responsibility practices of the financial services industry. The empirical study showed that the organisations under review did not have specific criteria that guide their selection of targets for social responsibility involvement. This highlighted an area of improvement on the social responsibility practices. The results of the literature study and the empirical investigation indicated that to be proactive in the field of social responsibility, criteria for selecting targets should be set and social responsibility practices should be linked to the corporate objectives and should form part of the strategic planning process. An affirmative approach to social responsibility will ensure that the two financial institutions be perceived as socially responsible.
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- Date Issued: 2002
The effect of energy and protein nutritional levels on production of breeding ostriches
- Authors: Brand, Zanell
- Date: 2002
- Subjects: Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5805 , http://hdl.handle.net/10962/d1006312 , Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Description: Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.
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- Date Issued: 2002