Response surface optimisation of medium components for naringinase production from staphylococcus xylosus MAK 2

Response surface methodology was used to optimize the fermentation medium for enhancing naringinase production by Staphylococcus xylosus. The first step of this process involved the individual adjustment and optimization of various medium components at shake flask level. Sources of carbon (sucrose) and nitrogen (sodium nitrate), as well as an inducer (naringin) and pH levels were all found to be the important factors significantly affecting naringinase production. In the second step, a 22 full factorial central composite design was applied to determine the optimal levels of each of the significant variables. A second-order polynomial was derived by multiple regression analysis on the experimental data. Using this methodology, the optimum values for the critical components were obtained as follows: sucrose, 10.0%; sodium nitrate, 10.0%; pH 5.6; biomass concentration, 1.58%; and naringin, 0.50% (w/v), respectively. Under optimal conditions, the experimental naringinase production was 8.45 U/mL. The determination coefficients (R ²) were 0.9908 and 0.9950 for naringinase activity and biomass production, respectively, indicating an adequate degree of reliability in the model.

Power and production in site-based management: the responses of women secondary principals to structural reform in South Australian education

After describing and analysing the purpose and shape of structural reform in Australia, the author uses the data gained from interviews with 16 South Australian women principals, to examine its effects on the work of principals. She uses her analysis to issue some warnings about the current moves to Local School Management in South Australia

Optimization of medium and process parameters for the production of inulinase from a newly isolated Kluyveromyces marxianus YS-1

A newly isolated strain of Kluyveromyces marxianus YS-1 was used for the production of extra cellular inulinase in a medium containing inulin, meat extract, CaCl₂ and sodium dodecyl sulphate (SDS). Fermentation medium pH 6.5, cultivation temperature 30 °C and 5% (v/v) inoculum of 12 h-old culture were optimal for enzyme production (30.8 IU/ml) with a fermentation time of 72 h at shake flask level. Raw inulin (2%, w/v) extracted from dahlia tubers by processing at 15 kg/cm² for 10 min was optimum for bioreactor studies. Maximum enzyme production (55.4 IU/ml) was obtained at an agitation rate of 200 rpm and aeration of 0.75 vvm in a stirred tank reactor with a fermentation time of 60 h.

Production of inulinase from Kluyveromyces marxianus YS-1 using root extract of Asparagus racemosus

Roots of Asparagus racemosus were used as a source of inulin for the production of inulinase from Kluyveromyces marxianus YS-1. Root extract prepared at 10 kg/cm² for 10 min showed the maximum production of inulinase. Various parameters of fermentation have been examined in order to improve overall enzyme yield. Inulinase yield of 40.5 IU/mL in an optimized medium containing inulin (3.5%), beef extract (0.5%), MnSO₄ (0.5 mM), CoCl₂ (0.05 mM), SDS (0.4 mM) and pH 6.5 at 30 °C under agitation (150 rpm) for 60 h has been obtained at shake flask level. After optimization the enzyme production has been increased 6.1 times at flask level. In a bioreactor (working volume 1 L) fermentation medium containing 4% inulin has shown maximum inulinase production (47.3 IU/mL) under optimized parameters of 200 rpm, 0.75 vvm aeration at 30 °C after 60 h.

Production and bioavailability of calcium and magnesium salts of omega-3 fatty acids

In order to provide an alternative to traditional liquid fish oil gelatin capsules, we developed a solid, powdered form of omega-3 fish oil concentrate by forming calcium- and magnesium-fatty acid salts. These salts were produced using a concentrated fish oil ethyl ester that contained in excess of 60% omega-3 fatty acids. The bioavailability of these omega-3 salts was compared with that of fish oil ethyl ester in mice. Animals were given 8 mg of omega-3 fatty acid ethyl ester concentrate (control), calcium- or magnesium-omega-3 salts daily for three weeks. The omega-3 salt products resulted in omega-3 fatty acid content in serum and red blood cell membranes comparable to that produced by the ethyl ester supplementation. In addition, fecal excretion of omega-3 fatty acids was not increased by the presence of calcium or magnesium. In fact, there was a tendency for less omega-3 fatty acids to be excreted.

Kristevan aesthetics, performativity and the production of situated knowledge

In this paper, I will draw on the work of Julia Kristeva to argue that performativity can be understood in terms of a materialist ontology that underpins creative production and the knowing subject. To understand this, we need to examine the relationship between individual history, biology and culture and processes through which creative practice attributes value by translating psychic representations of affect and drive into verbal and visual signs. Kristeva's aesthetics does not plunge us into an obscure metaphysics, but provides a model for articulating material-discursive practices that emerge from corporeal responses. Enactments, predicated by desire give rise to agency and judgement allowing practice to test theory through the production of situated knowledge.

Kristeva's psychoanalytical position reveals the necessity of linking material and individual practices of art with the social through language and interpretation. Material-discursive practices can only acquire meaning through their relationship between the speaking subject and addressees. Art itself provides us with the means for discovering the knowledge it produces. In and through material practice, the work of art is capable of transferring back to the artist as viewer, structures of meaning that have hitherto been hidden. In practice, this involves a constant movement between the biological self (the self as 'other') and the social self, the ego. In artistic research, it can be said that the first addressee is the artist her/himself, as social other. Constant movement between the two in creative practice can thus be understood as a performative production of knowledge.

Integrating farm production and natural resource management in Tasmania, Australia

This paper reports on the social learning from a project aimed to increase the knowledge and capacity of a group of farmers in Tasmania, Australia, to reduce the impacts of intensive agriculture on soil health and waterways, and to optimise the efficient use of on-farm inputs. The plan-do-check-review cycle adopted in this project required the farmers to assess current management practices, identify where to make changes, implement changes and monitor for improvements. The success of the project was due to careful attention to social processes as well as technical input. The combination of group activities with individual mentoring and one-to-one advice was key to the success of this project in enabling farmers to undertake on-farm action.

There is value in social learning that included developing relationships, using one-to-one contact and group workshops together with expert input when working with farmers to tackle some difficult and complex interrelated natural resource management and production issues. Sufficient time must be allowed for the process of facilitating good practice in natural resource management, particularly when addressing systemic environmental impacts. Practical operational recommendations are presented on communication, feedback, focus of activities and meeting content, as these will be useful to other project officers and facilitators working with farmer groups.

Alien species in aquaculture and biodiversity : a paradox in food production

Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local biodiversity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on biodiversity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on biodiversity.

Environmental art and the production of publics : responding to environmental change

Environmental crises around the world have inspired an outpour of creative response. As the effects of climate change increasingly manifest, environmental! art is being politically and pedagogically mobilised for ameliorative strategies. The rubric that instrumentalist, techno-scientific approaches to environmental stress (and attendant social distress) cannot solely provide solutions to this challenge has found increasing acceptance. The concern of this paper, however, is the limited understanding of public art's capacity that is perpetuated bv certain trends in environmental art in which the work is charged with communicative responsibility,. Connected to the representational and instructive traditions of public art, this tendency is further informed by the influence of the 'information-deficit model' in environmental conmunication research: a concept that asserts a straightforward connection between information provision, indiyidual awareness and collective action on a concern. The idea that public art can function as a conduit for knowledge,.which in turn will inspire new moral positions and behaviours, absents the art work from the process of knowledge-making and the production of conditons that enable new practice. Arguing for a revised approach to the environmental possibilities of public art, this paper will propose that in thinking aboutl environmental transformation as essentially unrepresentable, a dfferent mode of public engagement with the issue is enabled.

Rhizome / MyZone : the production of subjectivity in dance

[No Abstract]

Practising gender : the production of identity by school children

The thesis utilises ‘practice theory’ to argue that the self is not only an effect of social practices but also a technique for action and develops an alternative way of explicating and conceptualising the constitution of the self within the micro-practices of routine, everyday life. This is in contrast to a general tendency within ‘practice theory’, ‘constructionist’ and ‘discursive’ approaches towards a determinist conception of the self. The thesis explores this conceptual framework in fieldwork focussed on formation and production of gender-identity among young school children and offers a new perspective of gender-identity in the classroom. The thesis provides a fourfold contribution: (1) It provides insights into how in the classroom, children take up (conventional) gender differentiated conduct and dispositions in order to forge both their identity and the establishment of a social order based on gender. This gender order is not simply imposed on them by teachers but is actively constructed by the children. The thesis provides insights into how the children in the classroom seize and appropriate the practices of gender for their own ends. These ends, I argue, are the construction of their gender-identity, and the establishment and maintenance of a ‘matrix of intelligibility’. (2) It offers a close-up illustration of how gender construction is negotiated and contested between girls and boys. This is characterised as largely a struggle for enablement — the power to be and to do — rather than as a struggle of one gender over another. (3) It develops an analysis of classrooms as productive sites, as ‘complex strategical situations’ in which the participating agents — the teachers and students—deploy and utilise available resources in their ongoing construction of the world. This suggests that that the social world is not as unitary and totalising as ‘constraint perspectives’ within practice theory often imply. (4) It proposes methodological perspectives and strategies for researching empirically the day-to-day production of gender and for capturing that complex and often elusive process ‘in flight’. It shows the value of an ‘ascending analysis’, one that does not foreclose findings on the basis of a pre-existing theoretical position, and the rich potential of ‘flashpoints’ as a way of illuminating ongoing and often ‘unremarkable’ and therefore unnoticed practices of gender production. The theoretical terrain explored a range of theorists on the self not usually brought together, including Butler, Rose, Foucault, Giddens and Garfinkel and Schatzki. These theorists share in common the perspective that social practices rather than the agent or social totality are the ontological basis of the social world. It is argued that the self is constituted in its enactment and the thesis pursues Foucault’s (2002) question of how the self participates in its own subjectification. The empirical focus of the thesis examined the activities of children at school for insights into how they participated in the making of their gender-identity. The research addressed the questions: (1) To what extent do children construct their gender-identity and what kinds of encouragement do they receive for this? (2) To what extent did the children seem to be appropriating gender practices and inciting the making of gender-identity in the classroom? (3) To what extent can the classroom be viewed as a site of gender contestation and borderwork? Using the concept of ‘flashpoints’, — significant or poignant moments in the classroom — classroom activities were observed to catch gender-identity production ‘in flight’ and to describe how the children seize upon moments to make gender salient. Year Three children in five classrooms in two Victorian schools were observed during English communication and literacy lessons. Individual interviews with teachers in the participating schools and group interviews with the children from the classrooms were undertaken to amplify the observations. Much of the children’s behaviour can be interpreted as their efforts to make gender salient in social interactions. Gender-identity production and gender ‘border work’ (Thorne, 1993) and contestation appeared to be a major activity and preoccupation of the children, even in the face of teacher’s attempts to encourage a gender-neutral environment The children were often more active than the teachers in imposing the ‘gender agenda’ identified by Evans (1988). Overall, this thesis contributes to the development of the theory of subjectivity and identity formation. Social practices are not imposed and individuals seize upon social practices to further their own ends. It is through these routine, everyday activities that social practices are reproduced. The study provides an avenue for understanding the actions of children and the operation of gender power and border work within the classroom.

Production system model of children's development of number concepts

The purpose of the present research study was to produce a global, cumulative model of number concept development for children between the ages of two and eight years old. The theoretical and methodological orientation of this study was greatly influenced by Richard Young's production system analysis of seriation by young children (Young, 1971, 1976) and by Newell's (1973) seminal paper, ‘You can't play twenty questions with nature and win’. The methodology used in this investigation thus was as follows. A series of complex number tasks encompassing many aspects of the concept of number were developed. Five children aged between three and seven years then were videotaped while performing some of these complex number tasks. From a detailed protocol analysis of the video-recordings, computer simulation models written in the production system language PSS3 (Ohlsson, 1979) were produced. Specific production system models were produced for each of following aspects of the children's number knowledge: (i) sharing of discrete quantities; (ii) comparison of shares; and (iii) conservation/addition/subtraction of number. These domain-specific models were based on the converging experimental evidence obtained from each of the children’s responses to variants of the complex number tasks. Each child thus received a different set of problems which were chosen systematically in order to clarify particular features of the child's abilities. After a production system model for each child had been produced within a domain, these models were compared and contrasted. From this analysis, developmental trends within the domain were identified and discussed. The research and educational implications of these developmental trends then were discussed. In the concluding parts of this study, the children's domain-specific production system models were cumulated into global, comprehensive models which accurately represented their behaviour in a variety of number tasks. These comprehensive models were compared and contrasted and general developmental trends in young children's number knowledge were identified and discussed.

Effect of dietary arachidonic acid and n-3 polyunsaturated fatty acids on the production of eicosanoids

The major polyunsaturated fatty acid (PUFA) in the western diet is linoleic acid (LA), which is considered to be the major source of tissue arachidonic acid (AA), the principal precursor for the vaso-active eicosanoids via the cyclooxygenase enzymatic pathway. However, dietary AA may contribute significantly to tissue levels of AA in humans, leading to an increase in the production of eicosanoids, particularly the platelet aggregating, vasoconstricting, thromboxane (TXA2), hence increasing thrombosis risk. The aims of this study were to determine the extent to which dietary AA contributed to prostacyclin (PGI2) and TXA2 production in vivo and whether dietary long chain (LC) n-3 PUFA have a modulating influence on the metabolism of AA to these vaso-active eicosanoids. A gas chromatography -mass spectrometry (GCMS) method for urinary PGI2-M determination and a tandem GCMS/MS method for urinary TXA2-M determination were perfected for use within our laboratory (with the assistance of Dr Howard Knapp, University of Iowa and Professor Reinhard Lorenz, Ludwig Maximilian's University, Munich, respectively). An initial animal study compared the in vitro production of PGI2 by aorta segments with the whole body in vivo production of PGI2 in rats fed ethyl arachidonate or the ethyl ester of eicosapentaenoic acid (EPA), at levels many times higher than encountered in human diets. During AA feeding both measures of PGI2 increased, although in vitro TXA2 production was not affected. EPA feeding lowered in vitro TXA2 and in vivo PGI2. Prior to determining the effects of AA and LC n-3 PUFA in humans, a study was carried out to determine the AA and LC n-3 PUFA content of foods and from these, an estimate of the mean daily intake of AA and other LC PUFA. Eggs, organ meats and paté were found to be the richest sources of AA. Of the meat and fish analysed, white meat was found to be relatively rich in AA but poor in LC n-3 PUFA. Lean red meat, particularly kangaroo had similar LC n-3 PUFA and AA content. Fish, although rich in AA, had extremely high levels of LC n-3 PUFA. The calculated mean daily intakes of AA in Australian adults was 130mg (males) and 96mg (females). For total LC n-3 PUFA intake, the mean daily values were 247mg (males) and 197mg (females). Two human pilot studies involving dietary intervention trials examined the effects of dietary AA and AA plus long chain n-3 PUFA on thrombosis risk, gauged by the change in the ratio of PGI2 / TXA2 as well as alterations to other recognised risk factors, such as lipoprotein lipids and platelet aggregation. The desired dietary amounts of AA and LC n-3 PUFA were achieved in the first study by combining food items with known levels of each fatty acid. In the second study, where a diet with approximately equal quantities of AA and LC n-3 PUFA was being examined, kangaroo meat was consumed, following a low-fat vegetarian diet used as a baseline. Diets rich in AA alone (~500mg/day) increased plasma phospholipid (PL) AA levels, PGIi and TXA2 production. When foods containing equal quantities of AA and EPA (∼500mg/day of each) were fed to subjects PGI2 increased, with no change in TXAs production. Low fat vegetarian diets lowered PGI2 production, the level of which was reestablished by an AA rich diet (∼300mg AA/day + ∼260mg/day LC n-3 PUFA) of kangaroo meat. However, TXA2 production was not altered. A final, larger human dietary intervention trial then examined the effects of diets relatively rich in AA alone, AA plus LC n-3 PUFA and LC n-3 PUFA, on the ratio of PGI2/TXA2- The dietary sources of these fatty acids were white meat, red meat and fish, respectively. Each contained a mean level of AA of ∼140mg/day, with varying LC n-3 PUFA levels (59, 161 and 3380mg/day, respectively). Neither meat diet altered PGI2 or TXA2 production significantly, despite increasing serum PL AA levels. The fish diet resulted in a decrease in the serum and platelet PL AA/EPA ratio and TXA2 production, thus increasing the PGI2 / TXA2 ratio. These results would indicate that stores of AA in the body are sufficiently high to have effectively saturated the cyclooxygenase pathway for production of both PGI2 and TXA2, thus making any small change in the plasma level of AA due to 'normal' dietary levels, inconsequential. However, as seen in the rat study and the two pilot studies higher dietary levels of AA can increase both PGI2 and TXA2 production. Increases in platelet levels of EPA and DHA were associated with a decrease in TXA2 production, or the maintenance of a constant TXA2 level, while AA tissue levels and PGI2 production increased. This suggests a possible inhibitory effect of LC n-3 PUFA on the metabolism of AA to TXA2, particularly in platelets. From these short term studies, conducted over 2-3 week periods, it can be concluded that diets rich in lean meats can raise plasma AA levels but do not affect TXA2 or PGI2 production, hence are not pro-thrombotic. Diets rich in long chain n-3 PUFA from fish, raise plasma EPA and DHA levels, lower TXA2 production and are anti-thrombotic. Diets which combine equal quantities of AA and LC n-3 PUFA appear to increase PGI2 production while keeping TXA2 production constant. In order for these LC PUFA to have a significant effect on eicosanoid production the dietary intake of these fatty acids through foods such as red meat or white meat would have to be higher than average current Australian consumption levels.