Freshwater invertebrate fauna of the Tristan da Cunha islands (South Atlantic Ocean), with new records for Inaccessible and Nightingale Islands
- Authors: Barber-James, Helen M
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7001 , http://hdl.handle.net/10962/d1008360
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
- Full Text:
- Date Issued: 2007
Global diversity of mayflies (Ephemeroptera, Insecta) in freshwater
- Authors: Barber-James, Helen M , Gattolliat, Jean-Luc , Sartori, Michel , Hubbard, Michael D
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7002 , http://hdl.handle.net/10962/d1008361
- Description: The extant global Ephemeroptera fauna is represented by over 3,000 described species in 42 families and more than 400 genera. The highest generic diversity occurs in the Neotropics, with a correspondingly high species diversity, while the Palaearctic has the lowest generic diversity, but a high species diversity. Such distribution patterns may relate to how long evolutionary processes have been carrying on in isolation in a bioregion. Over an extended period, there may be extinction of species, but evolution of more genera. Dramatic extinction events such as the K-T mass extinction have affected current mayfly diversity and distribution. Climatic history plays an important role in the rate of speciation in an area, with regions which have been climatically stable over long periods having fewer species per genus, when compared to regions subjected to climatic stresses, such as glaciation. A total of 13 families are endemic to specific bioregions, with eight among them being monospecific. Most of these have restricted distributions which may be the result of them being the relict of a previously more diverse, but presently almost completely extinct family, or may be the consequence of vicariance events, resulting from evolution due to long-term isolation.
- Full Text:
- Date Issued: 2007
Freshwater invertebrate fauna of the Tristan da Cunha islands (South Atlantic Ocean), with new records for Inaccessible and Nightingale Islands
- Authors: Barber-James, Helen Margaret
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6940 , http://hdl.handle.net/10962/d1011964
- Description: As part of a multidisciplinary floristic-faunistic study, a three week survey of the invertebrate fauna of Inaccessible Island (South Atlantic Ocean) was carried out in October / November 1989. In addition, one day of collecting was done on Nightingale Island. This paper deals only with the fauna associated with freshwater ecosystems from these islands, some of which are usually associated with marine or brackish conditions. On Inaccessible Island, five distinct types of freshwater body were identified - pH neutral streams, acidic streams (pH 5), an open pool of standing water (pH 6), areas of acidic bog, and seepages down rock faces. The survey, the most comprehensive for Inaccessible Island to date, has resulted in the discovery of 19 aquatic invertebrate species previously unrecorded on Inaccessible Island, two new to Nightingale Island, and 14 of which are new to the Tristan da Cunha archipelago. Many of the species are known from other parts of the world, indicating a low degree of endemicity within the freshwater invertebrate community. Recolonisation from the source populations, preventing an isolated gene pool, may account for the low endemicity. Several of the species have a degree of salinity tolerance, enabling them to withstand transportation across tracts of ocean, and others have marine origins.
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- Date Issued: 2007
Bioremediation of trace organic compounds found in precious metals refineries wastewaters: A review of potential options
- Authors: Barbosa, V L , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6469 , http://hdl.handle.net/10962/d1005798 , http://dx.doi.org/10.1016/j.chemosphere.2007.01.018 , http://www.sciencedirect.com/science/article/pii/S0045653507001026
- Description: Platinum group metal (PGM) refining processes produce large quantities of wastewater, which is contaminated with the compounds that make up the solvents/extractants mixtures used in the process. These compounds often include solvesso, β-hydroxyxime, amines, amides and methyl isobutyl ketone. A process to clean up PGM refinery wastewaters so that they could be re-used in the refining process would greatly contribute to continual water storage problems and to cost reduction for the industry. Based on the concept that organic compounds that are produced biologically can be destroyed biologically, the use of biological processes for the treatment of organic compounds in other types of waste stream has been favoured in recent years, owing to their low cost and environmental acceptability. This review examines the available biotechnologies and their effectiveness for treating compounds likely to be contained in precious metal extraction process wastewaters. The processes examined include: biofilters, fluidized bed reactors, trickle-bed bioreactors, bioscrubbers, two-phase partitioning bioreactors, membrane bioreactors and activated sludge. Although all processes examined showed adequate to excellent removal of organic compounds from various gaseous and fewer liquid waste streams, there was a variation in their effectiveness. Variations in performance of laboratory-scale biological processes are probably due to the inherent change in the microbial population composition due to selection pressure, environmental conditions and the time allowed for adaptation to the organic compounds. However, if these factors are disregarded, it can be established that activated sludge and membrane bioreactors are the most promising processes for use in the treatment of PGM refinery wastewaters.
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- Date Issued: 2007
Dog Latin, Norman Morrissey : book review
- Authors: Beard, Margot
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6115 , http://hdl.handle.net/10962/d1003828
- Description: I have only seen one earlier collection of Morrissey's - his slim volume Seasons (1999). Therein he revealed his enjoyment and interest in haiku. Even the two longer poems in that volume were haiku-like, being brief self-contained stanzas grouped under a single title. His new volume, Dog Latin, consists of sixty short poems primarily concerned with man and nature. A number of these are haiku-like in their brevity ("Edgar on Inclusive Fitness," "Setting Ratbane," "Adam Again"), although they too often do not amount to more than post-it like notes. ("This habit / of holding habits to the wind / -me" is the sum total of the poem "Adam Again.") The epigraph to the whole collection is the final stanza of Robert Frost's "The Need of Being Versed in Country Things," which suggests both Morrissey's interest in the apparently unconsidered minutiae of natural objects and beings, and, it would seem, an admiration of Frost's deceptively plain, unmannered style.
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- Date Issued: 2007
Lessons from the dead masters: Wordsworth and Byron in J. M. Coetzee's Disgrace
- Authors: Beard, Margot
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6114 , http://hdl.handle.net/10962/d1003827
- Description: As one whose research interests lie in the field of Romanticism, most specifically Wordsworth and Byron, I was obviously intrigued by J. M. Coetzee's use of these poets in Disgrace. Subsequent readings of the work have convinced me that more attention needs to be paid to the deeper implications of their presence in the text. Certainly many scholars have explored the significance of David Lurie's professional interest in the Romantic poets and the novel's imbeddedness in what Jane Taylor has referred to as "the European Enlightenment's legacy of the autonomy of the individual" as well as a specifically "eighteenth century model of philosophical sympathy" (1999, 25). Yet I feel that insufficient attention has been paid to the significance of Romanticism, the Wordsworthian and the Byronic in the novel. Generally, the commentary ranges from seeing Lurie's academic interests as symptomatic of his white colonialist mentality to a more nuanced but insufficiently developed focus on the possibilities lying behind Coetzee's startling juxtaposition of two of the most famed and yet most overtly antagonistic of the Romantic poets. Zoë Wicomb is representative of the first approach. In her estimation, Lurie may be rejected since he "looks to Europe as the centre of reference" and "our feelings and experiences of nature need not be structured by poetic discourses from the metropolis".
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- Date Issued: 2007
Education is a spring… it bubbles
- Authors: Berger, Guy
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6333 , http://hdl.handle.net/10962/d1008478
- Description: [From the introduction]: Asians, Americans, Australians. A handful of Africans and a couple of Arabs. A sprinkling of Canadians, Mexicans, Finns. An Israeli, a Chilean and quite a few others. In total, 450 people from some 50 countries. In common: they’re all lecturers and trainers. Busy swopping notes in Singapore at the first-ever World Journalism Education Congress [WJEC] in July. It’s a resource-rich pool of ideas and experiences.
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- Date Issued: 2007
The comparison of in vitro release methods for the evaluation of oxytocin release from Pluronic® F127 parenteral formulations
- Authors: Chaibva, Faith A , Walker, Roderick B
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6351 , http://hdl.handle.net/10962/d1006033
- Description: The objective of these studies was to develop a discriminatory in vitro release test for assessing formulation factors that may affect oxytocin (OT) release during formulation development studies of a Pluronic® F127 OT in situ gel-forming parenteral dosage form. An appropriate release assessment method should be able to discriminate between the performance of different formulation compositions (1, 2), and this was the primary criterion used for selection of an appropriate test procedure during the test method development process. ANOVA and the difference (f1) and similarity (f2)factors were used to evaluate the discriminatory behavior of different test methods that were investigated in these studies. The in vitro release tests that were investigated included the use of USP Apparatus 1, 2, and 3; a dialysis bag in USP Apparatus 2; and a membrane-less diffusion method. It was concluded that the use of USP Apparatus 3 was best able to discriminate between OT release for the different formulations tested. USP Apparatus 3 was thus considered the most suitable in vitro release test apparatus for studying formulation factors affecting OT release during the development of a parenteral dosage form prepared using Pluronic® F127.
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- Date Issued: 2007
Load stress; carrier strain: implications for military and receational backpacking
- Authors: Charteris, J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6754 , http://hdl.handle.net/10962/d1009456
- Description: This paper reviews a growing literature on the stress of backpacking, particularly in military situations. Conceptual issues are raised and the implications for recreational backpackers are addressed. Under moderate to fairly heavy loading the energy cost, per kg total load carried, per hour, relates almost linearly to walking speed. Empirical data from studies in this unit are presented as benchmark indicators for use by recreational backpackers.
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- Date Issued: 2007
Spermiogenesis in three species of cicadas (Hemiptera: Cicadidae)
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6865 , http://hdl.handle.net/10962/d1011207
- Description: Spermiogenesis in three species of cicadas representing one cicadettine (Monomatapa matoposa Boulard) and two cicadines (Diceroprocta biconica [Walker] and Kongota punctigera [Walker]) was investigated by light and electron microscopy. Although spermiogenesis was occurring in the testis of adult males of all species, earlier spermiogenic stages were observed in D. biconica only. While spermiogenesis was similar to that described for other insects, some differences were noted. For example granular material did not assemble around the centriole to form a centriolar adjunct but did accumulate in the cytoplasm of early spermatids adjacent to a region of the nuclear membrane where nuclear pores were aggregated. In late spermatids this material accumulated anterior to the mitochondrial derivatives in a developing postero-lateral nuclear groove. While this material has been named the ‘centriolar adjunct’ by previous authors, its formation away from the centriole raises questions about its true identity. Second, during acrosome maturation an ante-acrosomal region of cytoplasm develops. Although present in later spermatids, this region is lost in spermatozoa. Interspecific variations in chromatin condensation patterns and the number of microtubule layers encircling the spermatid nucleus during spermiogenesis were noted.
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- Date Issued: 2007
Impact of nutrients and herbivory by Eccritotarsus catarinensis on the biological control of water hyacinth, Eichhornia crassipes
- Authors: Coetzee, Julie A , Byrne, Marcus J , Hill, Martin P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6945 , http://hdl.handle.net/10962/d1011973 , https://orcid.org/0000-0003-0579-5298
- Description: Many water hyacinth infestations in South Africa are the symptom of eutrophication, and as a result, biological control of this weed is variable. This study examined the effects of herbivory by the mirid, Eccritotarsus catarinensis, on water hyacinth grown at high, medium and low nitrogen (N) and phosphorus (P) nutrient concentrations. Water nutrient concentration appears to be the overriding factor affecting plant growth parameters of water hyacinth plants—at high nutrient concentrations, leaf and daughter plant production were more than double than at low nutrient concentrations, while stem length was twice as great at high nutrient concentrations compared to low concentrations. Chlorophyll content was also twice as high at high nutrient concentrations than low concentrations. Conversely, flower production at high nutrient concentrations was less than half that at low concentrations. Herbivory by E. catarinensis did not have as great an effect on water hyacinth vigour as nutrient concentration did, although it significantly reduced the production of daughter plants by 23 ± 9%, the length of the second petiole by 13 ± 5%, and chlorophyll content of water hyacinth leaves by 15 ± 6%. In terms of insect numbers, mirids performed better on plants grown under medium nutrient conditions (99 ± 28 S.E.), compared to high nutrient concentrations (52 ± 27 S.E.), and low nutrient concentrations (25 ± 30 S.E.). Thus, these results suggest that the fastest and most significant reduction in water hyacinth proliferation would be reached by lowering the water nutrient concentrations, and herbivory by E. catarinensis alone is not sufficient to reduce all aspects of water hyacinth vigour, especially at very high nutrient concentrations.
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- Date Issued: 2007
"He and His Man": allegory and catachresis in J. M. Coetzee's Nobel Lecture
- Authors: Cornwell, Gareth D N
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:2261 , http://hdl.handle.net/10962/d1004619
- Description: This essay offers a reading of J.M. Coetzee's 2003 Nobel Lecture, "He and His Man," a narrative featuring the characters of Robinson Crusoe and Daniel Defoe that borrows extensively from Defoe's Journal of the Plague Year (1722) and Tour through the Whole Island of Great Britain (1724-26). In it Coetzee whimsically explores several concerns of central importance for the activities of reading and writing, most notably the seemingly unavoidable (though ostensibly disabling) phenomenon of displacement or substitution that -- at its most generalizable level -- is best characterized as catachresis.
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- Date Issued: 2007
Towards a definition of SUBJECT in binding domains and subject-oriented anaphora
- Authors: de Vos, Mark
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6141 , http://hdl.handle.net/10962/d1011593
- Description: The question of subjecthood has dogged linguistic science since ancient times. However, in current versions of Minimalism, subjects do not have primitive status and can only be defined in derived terms. However, subjects and the broader theoretical notion of SUBJECT remain important in linguistic description. This paper develops a definition of subjecthood in terms of set-theoretic notions of functional dependency: when a feature, say phi, determines the value of some other feature, say u-phi. This notion is used to describe various phenomena where subjecthood has been invoked: binding domains and subject-oriented anaphors.
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- Date Issued: 2007
Resistance or tolerance: an examination of aphid (Sitobion yakini) phloem feeding on Betta and Betta-Dn wheat (Triticum aestivum)
- Authors: De Wet, L R , Botha, Christiaan E J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6517 , http://hdl.handle.net/10962/d1005945
- Description: Engineering pest resistance into crops is important. However, the mechanisms of resistance are not clearly understood. In this study, we examined the effects of aphid feeding on Russian wheat aphid-resistant and -susceptible cultivars of wheat (Triticum aestivum L.); Betta-Dn and Betta, respectively, by the grass aphid, Sitobion yakini (Eastop). These cultivars were grown with or without aphid colonies. In each case, we examined the plants specifically for the formation of wound callose associated with the phloem, using aniline blue and fluorescence microscopy. We observed that aphid feeding stimulated the formation of wound callose in the susceptible cultivar, but that callose was comparatively reduced in the resistant cultivar of wheat. In a separate series of experiments, the xenobiotic, 5, 6-carboxyfluorescein diacetate was applied to attached sink leaves, distal to feeding aphids. When leaf segments were examined four hours after application, little evidence of phloem transport of the fluorescent cleavage product, 5, 6-carboxyfluorescein (5, 6-CF), was evident below known aphid-probed sieve tubes. Low levels or absence of 5, 6-CF indicates that either the aphids have successfully redirected sap to themselves, or that the phloem is no longer functional. In contrast, 5, 6-CF transport was evident below sites of aphid probing in Betta-Dn, suggesting that the phloem was still capable of long-distance transport. In addition, callose deposition was reduced in Betta-Dn leaf phloem and it is surmised that transport was not as affected by aphid feeding in the resistant cultivar. This indicates that the ‘resistant’ wheat cultivar may in fact be tolerant to aphid feeding by successfully overcoming the nutrient drain that feeding aphids imposed on the phloem transport system.
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- Date Issued: 2007
Conceptualizing the human use of wild edible herbs for conservation in South African communal areas
- Authors: Dovie, Delali B K , Shackleton, Charlie M , Witkowski, Ed T F
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6626 , http://hdl.handle.net/10962/d1006818
- Description: The importance of wild edible herbaceous species to resource poor households in most rural economies within savannas has been little studied. This is because most of the herbs grow in impoverished species communities and lands, often referred to as ‘marginal lands’. The aim of this paper is to conceptualize how the economics of wild edible herbs to households can be used to add value to total livelihoods and conservation within traditional communal areas of South Africa. Analysis of the economics of the consumption of wild edible herbs in Thorndale (Bushbuckridge district) of the Limpopo province is presented. The majority of households consumed wild edible herbs, averaging 15.4 kg dried weight per household per year and valued at $167 per household. The herbs were mostly harvested from uncultivated areas of farms, and rangelands. There was little correlation between household characteristics and the dependence on wild herbs for food. The local people noted a decline in the availability of the species, although not much is known about attempts to cultivate them. The only reasons attributed to the decline were nutrient poor soils and insufficient rains. With this background, developing a local strategy to sustain the species through cultivation by households was found to be feasible. A multiple-use system for the herbs, their improvement and value addition towards commercialization and increased household usage may result in wider acceptance and subsequent cultivation. Species diversity will be enhanced whilst conserving the land on which they grow. This multiple use system may include species roles in soil and water conservation.
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- Date Issued: 2007
A few points on Pointfree pseudocompactness
- Authors: Dube, T , Matutu, Phethiwe P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6783 , http://hdl.handle.net/10962/d1006926
- Description: We present several characterizations of completely regular pseudocompact frames. The first is an extension to frames of characterizations of completely regular pseudocompact spaces given by Väänänen. We follow with an embedding-type characterization stating that a completely regular frame is pseudocompact if and only if it is a P-quotient of its Stone-Čech compactification. We then give a characterization in terms of ideals in the cozero parts of the frames concerned. This characterization seems to be new and its spatial counterpart does not seem to have been observed before. We also define relatively pseudocompact quotients, and show that a necessary and sufficient condition for a completely regular frame to be pseudocompact is that it be relatively pseudocompact in its Hewitt realcompactification. Consequently a proof of a result of Banaschewski and Gilmour that a completely regular frame is pseudocompact if and only if its Hewitt realcompactification is compact, is presented without the invocation of the Boolean Ultrafilter Theorem.
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- Date Issued: 2007
Collaborative versus adversarial stances in scientific discourse : implications for the role of systematic case studies in the development of evidence-based practice in psychotherapy
- Authors: Edwards, David J A
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6245 , http://hdl.handle.net/10962/d1007861
- Description: There is still a need for advocacy in the promotion of case study research because there has been insufficient appreciation of its role as a source of evidence relevant to the development and evaluation of practice in psychotherapy. Distorted use of terms like "gold standard", "anecdotal",and "empirical" in the discourse in which research methodology is typically presented has disempowered the practitioner's perspective and discredited the role of case-based knowledge building. The framework of evidence-based practice (EBP) recognizes the complementarity of different research methods and acknowledges the significance of casebased research. To spell out some of these complementary links, a typology of seven research methods - including both experimental group comparison designs and individual case studies - is proposed and the contribution of each to the development of EBP is set out. Finally some suggestions are made for strategies to promote the publication of high quality case studies.
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- Date Issued: 2007
Restructuring implicational meaning through memory-based imagery: some historical notes
- Authors: Edwards, David J A
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6239 , http://hdl.handle.net/10962/d1007851
- Description: This paper provides a historical perspective on the recent increase in the clinical application of imagery techniques to restructure systems of implicational meaning that drive emotional distress or self-defeating behaviors. Janet's early application of such techniques was largely ignored except by a few hypnotherapists. Current applications in cognitive therapy were adapted and extended in the early 1980s from Perls’ Gestalt therapy methods. Some precursors to Perls are examined, as well as the work of some of those who developed and formulated the integration of his techniques into Beck's cognitive therapy. It is argued that this process amounted to a significant paradigm shift.
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- Date Issued: 2007
"Muscled Presence": Douglas Livingstone's poem "Thirteen Ways of Looking at a Black Snake"
- Authors: Everitt, M , Wylie, D
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:2262 , http://hdl.handle.net/10962/d1004642
- Description: Douglas Livingstone's poem "Thirteen Ways of Looking at a Black Snake" is an artwork which addresses precisely these questions, seeking a manner of portraying the snake which is neither grossly appropriative nor wholly detached, neither ethically empty nor preachy. In its multi-angled structure, Livingstone attempts aesthetically "to establish and embellish ... a contact zone with the nonhuman animals who share our world with us, but accepting also that there exist considerable venues on either side of this contact zone that are, on the one hand, only human, and on the other hand, only nonhuman". Even in his more formally scientific work, Livingstone argues for the inevitability of such limits to knowledge, and for the value of the imagination in addressing them.
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- Date Issued: 2007
Gowin's Knowledge Vee and the integration of philosophy and methodology : a case study
- Authors: Fox, Roddy C
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6682 , http://hdl.handle.net/10962/d1006677
- Description: Universities with a strong research tradition commonly have courses or modules examining the tradition’s philosophies and methodologies to prepare their students to undertake research programmes. Recently, however, authors have called for wider debate concerning how we teach these courses and this paper is intended, in part, to make a contribution to this debate. The Research Philosophy and Methodology module examined here makes an intriguing case study because of a number of distinctive characteristics. The teaching philosophy of the module is social constructivist and it uses Gowin’s Knowledge Vee as its main heuristic device. This facilitates the construction of knowledge about philosophy and methodology in an integrated manner. The module has also been designed for both physical and human geography students at the introductory post-graduate level. There is, therefore, a second element of integration in the curriculum. Lastly, the module is predominantly web-based, being taken by distance students through the exchange agreement between Rhodes University, South Africa, and the University of Trollhättan-Uddevalla, Sweden. Evidence from reflective exercises shows that the learners’ understanding of research and the research process has deepened considerably through using Gowin’s Vee. Furthermore, using the Knowledge Vee in the web-based context has facilitated the integrative aspects of the module.
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- Date Issued: 2007