Factors affecting the activity of baker's compressed and active dry yeast : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology at Massey University

Factors affecting the Activity of Baker's Compressed and Active Dry Yeast. Parameters important in the production of Baker's Yeast were correlated with the product's final activity. Activity was a measure of the gas evolved in a fermenting dough, expressed as mMCO2/hr/g yeast solids. The drying of Compressed Yeast to Active Dry Yeast was optimised in terms of the drying air. A tunnel tray drier was used to dry yeast to a 9% moisture content (dry weight). At 40°C. the optimum drying humidity was found to be 30-32% relative humidity. The leavening ability of yeast dried at 17% and 45% relative humidity decreased. A drying additive, 2% glyceryl monostearate, halved the drying time to 4 hours. Equations were developed to describe these observations as a function of relative humidity, drying time and additive concentration. The equilibrium relative humidity of stored dried yeast was found to be 32% at 20°C. Fermentation parameters were correlated with the activity of Compressed Yeast using an experimental design. Growth temperatures varied from 28°C. to 37°C., initial pH from 4 to 6, glucose concentrations from 0.5% to 3%, nitrogen concentrations from 0.3% to 1.2% and dissolved oxygen varied as either agitated or standing cultures. Factors significantly affecting cell yield and yeast activity were growth temperature, dissolved oxygen and glucose concentrations. Maximal yeast activity occurred at 0.5% glucose concentration, 28°C. and non-agitated conditions. A model was developed to describe yeast activity as a function of these variables. The observed optimal conditions for cell yield were similar to those for yeast activity except for the dissolved oxygen level. Maximum yeast activity of Compressed Yeast occurred in non-agitated fermentations, compared with cell yield which required agitated conditions to achieve the greatest cell yield. A rapid screening test for evaluating dried yeast was incorporated into the yeast activity analysis. This involved monitoring foam production during rehydration

Dark Radiation in Anisotropic LARGE Volume Compactifications

Dark radiation is a compelling extension to $\Lambda$CDM: current experimental results hint at $\Delta N_{\rm eff} \gtrsim 0.5$, which is increased to $\Delta N_{\rm eff} \simeq 1$ if the recent BICEP2 results are included. In recent years dark radiation has been considered in the context of string theory models such as the LARGE Volume Scenario of type IIB string theory, forging a link between present-day cosmological observations and models of physics at the Planck scale. In this paper I consider an extension of the LARGE Volume Scenario in which the bulk volume is stabilised by two moduli instead of one. Consequently, the lightest modulus no longer corresponds to the compactification volume but instead to a transverse direction in the bulk geometry. I focus on scenarios in which sequestering of soft masses is achieved by localising the Standard Model on D3 branes at a singularity. The fraction of dark radiation produced in such models vastly exceeds experimental bounds, ruling out the sequestered LARGE Volume Scenario with two bulk moduli as a model of the early Universe.Comment: 12 pages, no figures; v3 - expanded discussions, clarified terminology, corrected error in equation (3.11); version to be published in JHE

Protist predation can favour cooperation within bacterial species

Here, we studied how protist predation affects cooperation in the opportunistic pathogen bacterium Pseudomonas aeruginosa, which uses quorum sensing (QS) cell-to-cell signalling to regulate the production of public goods. By competing wild-type bacteria with QS mutants (cheats), we show that a functioning QS system confers an elevated resistance to predation. Surprisingly, cheats were unable to exploit this resistance in the presence of cooperators, which suggests that resistance does not appear to result from activation of QS-regulated public goods. Instead, elevated resistance of wild-type bacteria was related to the ability to form more predation-resistant biofilms. This could be explained by the expression of QS-regulated resistance traits in densely populated biofilms and floating cell aggregations, or alternatively, by a pleiotropic cost of cheating where less resistant cheats are selectively removed from biofilms. These results show that trophic interactions among species can maintain cooperation within species, and have further implications for P. aeruginosa virulence in environmental reservoirs by potentially enriching the cooperative and highly infective strains with functional QS system

O(D,D)\mathbf{O}(D,D) completion of the Friedmann equations

In string theory the closed-string massless NS-NS sector forms a multiplet of $\mathbf{O}(D,D)$ symmetry. This suggests a specific modification to General Relativity in which the entire NS-NS sector is promoted to stringy graviton fields. Imposing off-shell $\mathbf{O}(D,D)$ symmetry fixes the correct couplings to other matter fields and the Einstein field equations are enriched to comprise $D^{2}+1$ components, dubbed recently as the Einstein Double Field Equations. Here we explore the cosmological implications of this framework. We derive the most general homogeneous and isotropic ansatzes for both stringy graviton fields and the $\mathbf{O}(D,D)$-covariant energy-momentum tensor. Crucially, the former admits space-filling magnetic $H$-flux. Substituting them into the Einstein Double Field Equations, we obtain the $\mathbf{O}(D,D)$ completion of the Friedmann equations along with a generalized continuity equation. We discuss how solutions in this framework may be characterized by two equation-of-state parameters, $w$ and $\lambda$, where the latter characterizes the relative intensities of scalar and tensor forces. When $\lambda+3w=1$, the dilaton remains constant throughout the cosmological evolution, and one recovers the standard Friedmann equations for generic matter content (i.e. for any $w$). We further point out that, in contrast to General Relativity, neither an $\mathbf{O}(D,D)$-symmetric cosmological constant nor a scalar field with positive energy density gives rise to a de Sitter solution.Comment: v2: 31 + 13 pages; 1 figure. References added; abstract amended; discussion amended and clarified throughout. Results unchanged. To be published in EPJC. v1: 28 + 12 pages (main body + title, appendix, and references); 1 figur

Survey Design and the Determinants of Subjective Wellbeing: An Experimental Analysis

We analyse the results of experiments on questionnaire design and interview mode in the first four waves (2008-11) of the UK Understanding Society Innovation Panel survey. The randomised experiments relate to job, health, income, leisure and overall life-satisfaction questions and vary the labeling of response scales, mode of interviewing, and location of questions within the interview. We find significant evidence of an influence of interview mode and question design on the distribution of reported satisfaction measures, particularly for women. Results from the sort of conditional modeling used to address real research questions appear less vulnerable to design influences

Evaluating emotional distress and health-related quality of life in patients with heart failure and their family caregivers:Testing dyadic dynamics using the Actor-Partner Interdependence Model

Purpose: 1) To compare levels of emotional symptoms and health-related quality of life between patients with heart failure and their family caregivers; and 2) to examine whether patients’ and caregivers’ emotional symptoms were associated with their own, as well as their partner’s health-related quality of life. Method: In this cross-sectional study, 41 patients-caregiver dyads (78% male patients, aged 68.6 years; and 83% female caregivers, aged 65.8 years) completed all nine dimensions of the Brief Symptom Inventory and the Minnesota Living with Heart failure Questionnaire. Dyadic data were analysed for 6 sub-scales of the Brief Symptom Inventory, using the Actor–Partner Interdependence Model. Results: There were no statistically significant differences in emotional symptoms and health-related quality of life between patients with heart failure and their caregivers. Patients’ and caregivers’ emotional symptoms were associated with their own health-related quality of life. Caregivers’ anxiety, phobic anxiety, obsession-compulsion, depression and hostility negatively influenced their partner’s (i.e. the patient’s) health-related quality of life. There were no partner effects of patients’ emotional symptoms on the health-related quality of life of caregivers. Conclusions: The results of this study suggest that patients may be particularly vulnerable to the emotional distress, i.e. thoughts, impulses and actions of their caregivers. It may be possible to improve patients’ health-related quality of life by targeting specific detrimental emotional symptoms of caregivers

Improving access to a multi-component intervention for caregivers and people with dementia

Acknowledgements We thank staff and volunteers from Voluntary Service Aberdeen, Forget Me Not Club, NHS Grampian, Alzheimer’s Scotland, Quarrier’s Carer Support, and Aberdeenshire Council who participated as trainers, and Zahid Quayyum at the Health Economics Research Unit of the University of Aberdeen who contributed to the economic analysis. Funding The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Aberdeenshire Change Fund (Study 1), NHS Grampian Carers Information Strategy and Alzheimer Scotland (Study 2).Peer reviewedPostprin

Briefing: UK Ministry of Defence Force Protection Engineering Programme

The Defence Science and Technology Laboratory sponsored, QinetiQ-led Force Protection Engineering Research Programme has two main strands, applied and underpinning research. The underpinning strand is led by Blastech Ltd. One focus of this research is into the response of geomaterials to threat loading. The programme on locally won fill is split into four main characterisation strands: high-stress (GPa) static pressure–volume; medium-rate pressure–volume (split Hopkinson bar); high-rate (flyer plate) pressure–volume; and unifying modelling research at the University of Sheffield, which has focused on developing a high-quality dataset for locally won fill in low and medium strain rates. With the test apparatus at Sheffield well-controlled tests can be conducted at both high strain rate and pseudo-static rates up to stress levels of 1 GPa. The University of Cambridge has focused on using one-dimensional shock experiments to examine high-rate pressure–volume relationships. Both establishments are examining the effect of moisture content and starting density on emergent rate effects. Blastech Ltd has been undertaking carefully controlled fragment impact experiments, within the dataspace developed by the Universities of Sheffield and Cambridge. The data from experiments are unified by the QinetiQ-led modelling team, to predict material behaviour and to derive a scalable locally won fill model for use in any situation

Increasing physical activity in older adults using STARFISH, an interactive smartphone application (app); a pilot study

Background:Increasing physical activity in older adults has preventative and therapeutic health benefits. We have developed STARFISH, a smartphone application, to increase physical activity. This paper describes the features of STARFISH, presents the views of older users on the acceptability and usability of the app and reports the results of a six week pilot study of the STARFISH app in older adults. Methods:The operationalisation of the behaviour change techniques (BCTs) within the STARFISH app was mapped against the BCT Taxonomy of Michie et al. Sixteen healthy older adults (eight women and eight men; age 71.1 ± 5.2 years) used the app, in groups of four, for six weeks. Focus groups explored the user experience and objective measure of steps per day recorded. Results:Participants were very positive about using the STARFISH app, in particular the embedded BCTs of self-monitoring, feedback and social support (in the form of group rewards). Objective step data, available for eight participants, showed that step counts increased by an average of 14% (p = 0.077, d = 0.56). Conclusion:The STARFISH app was acceptable and straightforward to use for older adults. STARFISH has potential to increase physical activity in older adults; however, a fully powered randomised controlled trial is required