Aspects of the production of viscous capsular material by the yoghurt starter, streptococcus thermophilus

The technology of modern fermented milk production is not complicated and relies largely on the characteristics of the microorganisms used in its manufacture. Biochemical substances excreted by the starter cultures contribute to the chemical, physical and organoleptic properties of cultured milks. Chemical and organoleptic properties of yoghurt starter cultures have been widely studied over several decades. Conversely the biosynthetic processes and genetic control of the production of viscous extracellular material (slime) by selected thermophillic streptococci is still insufficiently understood. This study attempted to elucidate physiological aspects and the genetic control of slime production. An attempt to chemically induce ropiness was also preformed. Twenty strains of Gram positive, thermo-tolerant, milk dotting, catalase negative cocci were collected from a variety of sources. All strains were identified as Streptococcus thermophilus. Four of the isolates were identified as capable of producing an extracellular, ‘ropy’ capsular material. A negative staining method for highlighting capsular material under light microscopy was described. Ropy isolates displayed thick capsular zones of between 6-8 μm. The isolates graded as non-ropy produced only small capsular zones (less than 2 μm); two variants displayed no capsular material. Instability of the ropy phenotype during subculture and prolonged storage was described for all four ropy isolates at varied temperatures. Instability during transfer was reported as moderate with a loss of no more than 45% of ropy colonies after 15 subcultures at 48°C A significant increase in instability, during transfer, associated with an increase in incubation temperature (37-48°C) was also reported. Prolonged storage of ropy variants over ten days resulted in a drop in the number of ropy colonies. The loss was minimal when cultures were stored at 8°C, but excessive (approaching 100%) at 37°C This suggested the presence of capsular degradative substances. Analysis of the plasmid profiles of 20 strains identified only two strains harboured plasmid DNA. All plasmids were small, less than 23kilobases, and each strain possessed a single plasmid species. Only one ropy strain contained plasmid DNA that was shown, with the aid of curing experiments, not to be linked to production of the ropy phenotype. The amino acid analogue p-fluoro-DL-phenylalanine was unsuccessful in generating ropy colonies from non-ropy variants of Streptococcus thermophilus at low concentrations. Some technological considerations for the use of ropy variants of Streptococcus thermophilus in yoghurt starter cultures were made.

Structural equation modelling : tips for getting started with your research

At a time when numerical expression of data is becoming more important in the business of obtaining grant money research tools such as structural equation modelling (SEM) are becoming more popular. Structural equation modelling enables researchers to show relationships between variables numerically. It is of particular use to educational researchers who are interested in developing or using standard questionnaires in their research. This session will introduce SEM and explore its uses in educational research to enable the reader to decide whether it is a tool to use to add an extra dimension to their research findings.

Economic accountability in the context of local governance in the Philippines : a structural equation modelling approach

This study posits that by virtue of the enabling role of local governments, the economic development of their locality must be at the core of their public accountability, which is referred to here as “economic accountability”. Grounded on this idea of accountability, along with enabling theory and institutional theory, the study presents empirical evidence supportive of the argument that the enabling role of local governments, as manifested in a capacity to establish or adhere to formal institutional arrangements, has a direct impact on the entrepreneurial strategic posture and performance of local small and medium enterprises (SMEs) which are key players in local economic development.The results of the structural equation modelling support the view that institutional arrangements as manifestations of the enabling role of city governments are positively associated with an entrepreneurial strategic posture of local firms, which consequently improves the firms’ overall economic performance. Therefore, SME development in particular, and local economic development in general, should be part of the economic accountability of local governments in the Philippine context of local governance.

Work : A poetics of endurance within the viscous solo

This project developed a new approach to movement practice and performance through a solo performance that used physical paradigms of endurance and work to integrate the normally divergent movement practices of contemporary dance, circus and improvisation. This work contributes to developing dance and movement curricula relevant to contemporary hybrid aesthetics.

Structural equation modeling for evaluating the user perceptions of E-learning effectiveness in higher education

A crucial prerequisite for sustainable e-learning is the understanding of learners’ preferences for various pedagogical strategies, technologies, and the management of learning resources. This paper presents an empirical study aiming to empirically test the theoretical (pedagogies, technologies and management) (PTM) model on the preference of learners and on the perceived impact of the effectiveness of e-learning. This study uses structural equation modelling (SEM) to identify the critical dimensions in the PTM model for augmenting the effectiveness of e-learning. This leads to the development of a PTM model with the path coefficients showing weak to strong relationships ranging from 0.15 to 0.42 with acceptable significance levels. The results support the hypothesis that management, technology, resources and metadata ontology dimensions affect the effectiveness of elearning both directly and indirectly through enhancing the management effectiveness of learning resources. However, the result does not support positive influence of pedagogical strategy per se on e-learning effectiveness. The implications of this study indicate the criticality of effective management of learning resources to enhance e-learning effectiveness.

The addition of depression to the Framingham Risk Equation model for predicting coronary heart disease risk in women

BACKGROUND: Depression is widely considered to be an independent and robust predictor of Coronary Heart Disease (CHD), however is seldom considered in the context of formal risk assessment. We assessed whether the addition of depression to the Framingham Risk Equation (FRE) improved accuracy for predicting 10-year CHD in a sample of women.

DESIGN: A prospective, longitudinal design comprising an age-stratified, population-based sample of Australian women collected between 1993 and 2011 (n=862).

METHODS: Clinical depressive disorder was assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID-I/NP), using retrospective age-of-onset data. A composite measure of CHD included non-fatal myocardial infarction, unstable angina coronary intervention or cardiac death. Cox proportional-hazards regression models were conducted and overall accuracy assessed using area under receiver operating characteristic (ROC) curve analysis.

RESULTS: ROC curve analyses revealed that the addition of baseline depression status to the FRE model improved its overall accuracy (AUC:0.77, Specificity:0.70, Sensitivity:0.75) when compared to the original FRE model (AUC:0.75, Specificity:0.73, Sensitivity:0.67). However, when calibrated against the original model, the predicted number of events generated by the augmented version marginally over-estimated the true number observed.

CONCLUSIONS: The addition of a depression variable to the FRE equation improves the overall accuracy of the model for predicting 10-year CHD events in women, however may over-estimate the number of events that actually occur. This model now requires validation in larger samples as it could form a new CHD risk equation for women.