Community policing : tentative steps towards true reconciliation : inaugural lecture delivered at Rhodes University

Inaugural lecture delivered at Rhodes UniversityRhodes University Libraries (Digitisation

Spectral Analysis of a Four Mode Cluster State

We theoretically evaluate the squeezed joint operators produced in a single optical parametric oscillator which generates quadripartite entangled outputs, as demonstrated experimentally by Pysher et al. \cite{pysher}[Phys. Rev. Lett. 107, 030505 (2011)]. Using a linearized fluctuation analysis we calculate the squeezing of the joint quadrature operators below threshold for a range of local oscillator phases and frequencies. These results add to the existing theoretical understanding of this potentially important system.Comment: 4 pages, 6 figure

Integration of Peripheral and Glandular Regulation of Triiodothyronine Production by Thyrotropin in Untreated and Thyroxine-Treated Subjects

Objective: We evaluated the roles of central and peripheral T3 regulation. Design and Methods: In a prospective study involving 1796 patients the equilibria between FT3 and TSH were compared in untreated and L-T4-treated patients with varying functional states, residual thyroid secretory capacities and magnitudes of TSH stimulation. Results: T3 concentrations were stable over wide variations in TSH levels (from 0.2 to 7 mU/l) and endogenous T4 production in untreated patients, but unbalanced in L-T4-treated athyreotic patients where T3 correlated with exogenous T4 supply. T3 stability was related to TSH-stimulated deiodinase activity by clinical observation, as predicted by theoretical modelling. Deiodinase activity in treated patients was reduced due to both diminished responsiveness to TSH and lack of thyroidal capacity. Deiodinase activity was increased in high thyroid volume, compared to lower volumes in euthyroid patients (< 5 ml, p<0.001). While deiodinase differed between euthyroid and subclinically hypothyroid patients in high volume, 26.7 nmol/s (23.6, 29.2), n=214 vs 28.9 nmol/s (26.7, 31.5), n=20, p=0.02, it was equivalent between the two functional groups in low volume, 23.3 nmol/s (21.3, 26.1), n=117 vs 24.6 nmol/s (22.2, 27.5), n=38, p=0.22. Conclusions: The findings suggest that the thyroid gland and peripheral tissues are integrated in the physiological process of T3 homeostasis in humans via a feed-forward TSH motif, which coordinates peripheral and central regulatory mechanisms. Regulatory and capacity deficiencies collectively impair T3 homeostasis in L-T4-treated patients

The consequences of replicating in the wrong orientation: Bacterial chromosome duplication without an active replication origin

Chromosome replication is regulated in all organisms at the assembly stage of the replication machinery at specific origins. In Escherichia coli the DnaA initiator protein regulates the assembly of replication forks at oriC. This regulation can be undermined by defects in nucleic acid meta¬bolism. In cells lacking RNase HI replication initiates indepen¬dently of DnaA and oriC, presumably at persisting R-loops. A similar mechanism was assumed for origin-independent synthesis in cells lacking RecG. However, recently we suggested that this synthesis initiates at intermediates resulting from replication fork fusions. Here we present data suggesting that in cells lacking RecG or RNase HI origin-independent synthesis arises by different mechanisms, indicative of these two proteins having different roles in vivo. Our data support the idea that RNase HI processes R-loops, while RecG is required to process replication fork fusion intermediates. However, regardless of how origin-independent synthesis is initiated, a fraction of forks will proceed in an orientation opposite to normal. We show that the resulting head-on encounters with transcription threaten cell viability, especially if taking place in highly-transcribed areas. Thus, despite their different functions, RecG and RNase HI are both important factors for maintaining replication control and orientation. Their absence causes severe replication problems, highlighting the advantages of the normal chromosome arrangement, which exploits a single origin to control the number of forks and their orientation relative to transcription, and a defined termination area to contain fork fusions. Any changes to this arrangement endanger cell cycle control, chromosome dynamics and, ultimately, cell viability.This work was supported by the Royal Society (RG110414 to C.J.R.) and The Biotechnology and Biological Sciences Research Council (BB/K015729/1 to C.J.R.)

Adopting Minds — a mentalization-based therapy for families in a post-adoption support service: preliminary evaluation and service user experience

Children placed for adoption often face unique challenges and are at higher risk of mental health problems compared to the general population. Yet despite some important clinical developments, there is still a lack of evidence related to effective therapeutic interventions for this population. This study reports on the preliminary evaluation of a mentalization-based family therapy service, Adopting Minds, offered as part of a post-adoption support service. Thirty-six families who had adopted 42 children were referred to the service between September 2015 and December 2016. Demographic information was collected and assessments undertaken on the families at baseline and at the end of therapy, using a range of validated measures. Five families who had completed therapy were also interviewed about their experience of the approach. For those families on which data were available, positive outcomes in mental health and parental self-efficacy were identified, and adoptive parents reported high levels of satisfaction with the mentalization-based family therapy service. Analysis of the interviews revealed that the families found it a containing space that was supportive and non-judgemental. They felt able to express their fears and worries to a therapist who was friendly and knowledgeable and reported that the service helped them to deal with and link struggles they were facing to their own as well as their child's past experiences. However, some adoptive families felt that this short-term, six-session service alone was not enough to address all the difficulties that had brought the family to seek help, and would have preferred a longer-term intervention or therapy in combination with other types of support

Analysis of a continuous-variable quadripartite cluster state from a single optical parametric oscillator

We examine the feasibility of generating continuous-variable multipartite entanglement in an intra-cavity quadruply concurrent downconversion scheme that has been proposed for the generation of cluster states by Menicucci \textit{et al.} [Physical Review Letters \textbf{101}, 130501 (2008)]. By calculating optimized versions of the van Loock-Furusawa correlations we demonstrate genuine quadripartite entanglement and investigate the degree of entanglement present. Above the oscillation threshold the basic cluster state geometry under consideration suffers from phase diffusion. We alleviate this problem by incorporating a small injected signal into our analysis. Finally, we investigate squeezed joint operators. While the squeezed joint operators approach zero in the undepleted regime, we find that this is not the case when we consider the full interaction Hamiltonian and the presence of a cavity. In fact, we find that the decay of these operators is minimal in a cavity, and even depletion alone inhibits cluster state formation.Comment: 26 pages, 12 figure

A novel method for predicting the response variability of friction-damped gas turbine blades

Predicting the response of gas turbine blades with underplatform friction dampers is challenging due to the combination of frictional nonlinearity and system uncertainty: a traditional Monte Carlo approach to predicting response distributions requires a large number of nonlinear simulations which is computationally expensive. This paper presents a new approach based on the principle of Maximum Entropy that provides an estimate of the response distribution that is approximately two orders of magnitude faster than Monte Carlo Harmonic Balance Method simulations. The premise is to include the concept of `computational uncertainty': incorporating lack of knowledge of the solution as part of the uncertainty, on the basis that there are diminishing returns in computing precise solutions to an uncertain system. To achieve this, the method uses a describing function approximation of the friction-damped part of the system; chooses an ignorance prior probability density function for the complex value of the describing function based on Coulombs friction law; updates the distribution using an estimate of the mean solution, the admissible domain of solutions, and the principle of Maximum Entropy; then carries out a linear Monte Carlo simulation to estimate the response distribution. The approach is validated by comparison with HBM simulations and experimental tests, using an idealised academic system consisting of a periodic array of beams (with controllable uncertainty) coupled by single-point friction dampers. Comparisons with two- and eight-blade systems show generally good agreement. Predicting the response statistics of the maximum blade amplitude reveals specific well-understood circumstances when the method is less effective. Predictions of the overall blade response statistics agree with Monte Carlo HBM extremely well across a wide range of excitation amplitudes and uncertainty levels. Critically, experimental comparisons reveal the care that is needed in accurately characterising uncertainty in order to obtain agreement of response percentiles. The new method allowed fast iteration of uncertainty parameters and correlations to achieve good agreement, which would not have been possible using traditional methods.Mitsubishi Heavy Industrie

Predicting response bounds for friction-damped gas turbine blades with uncertain friction coupling

Friction dampers are often used to reduce high amplitude vibration within gas turbines: they are a robust solution that are able to withstand extreme operating environments. Although the turbine blades are manufactured to tight tolerances, there can be significant variability in the overall response of the assembly. Uncertainties associated with the frictional contact properties are a major factor contributing to this variability. This paper applies a recently developed method for predicting response bounds to friction-damped gas turbines when the characteristics of the friction dampers are unknown, including uncertainty regarding the underlying functional form of the friction law. The approach taken is to represent the frictional contact using a describing function, and formulate an optimisation problem to seek upper and lower bounds on a chosen response metric, such as displacement amplitude. Constraints are chosen that describe known properties of the frictional nonlinearity, without needing to specify a particular constitutive law. The method was validated by comparison with numerical and experimental results from an idealised test system. The experimental test rig consisted of an array of eight beams coupled by pin-contact friction dampers. A modal description of this test rig formed the basis of a numerical model, which uses the Harmonic Balance Method (HBM) for nonlinear simulations. A set of Monte Carlo tests was carried out numerically and experimentally for both a two-beam sub-assembly as well as for the full eight-beam assembly. Comparisons with numerical results showed excellent agreement providing confident verification of the implementation, and comparisons with experimental results revealed that the bounds became less conservative as the system complexity increased. Overall the results are promising: upper and lower response bounds for an array of friction-damped systems can be computed at similar cost to a single HBM simulation, giving reliable bounds that are valid for both parametric and model uncertainties associated with the friction couplings.Mitsubishi Heavy Industrie

A systematic review of shared decision making interventions in child and youth mental health: synthesising the use of theory, intervention functions, and behaviour change techniques

Reviews around interventions to improve shared decision making (SDM) for child and youth mental health have produced inconclusive findings on what approaches increase participation. Importantly, the previous reviews did not explore the use of theory, as well as mechanisms of change (intervention functions) and active units of change (behaviour change techniques). The aim of this review was to explore these factors and ascertain how, if at all, these contribute to SDM. Five databases were searched up until April 2020. Studies met inclusion criteria if they were: (a) an intervention to facilitate SDM; (b) aimed at children, adolescence, or young people aged up to 25, with a mental health difficulty, or their parents/guardians; and (c) included a control group. Data were extracted on patient characteristics, study design, intervention, theoretical background, intervention functions, behaviour change techniques, and SDM. Quality assessment of the studies was undertaken using the Effective Public Health Practice Project (EPHPP) quality assessment tool. Eight different interventions met inclusion criteria. The role of theory to increase SDM remains unclear. Specific intervention functions, such as 'education' on SDM and treatment options and 'environmental restructuring' using decision aids, are being used in SDM interventions, as well as 'training' for clinicians. Similarly, behaviour change techniques linked to these, such as 'adding objects to the environment', 'discussing pros/cons', and clinicians engaging in 'behavioural practice/rehearsal'. However, as most studies scored low on the quality assessment criteria, as well as a small number of studies included and a low number of behaviour change techniques utilised, links between behaviour change techniques, intervention functions and increased participation remain tentative. Intervention developers and clinicians may wish to consider specific intervention functions and behaviour change techniques to facilitate SDM