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Synthetic observations of spiral arm tracers of a simulated Milky Way analog
No full textContext. The Faraday rotation measure (RM) is often used to study the magnetic field strength and orientation within the ionized medium of the Milky Way. Recent observations indicate an RM magnitude in the spiral arms that exceeds the commonly assumed range. This raises the question of how and under what conditions spiral arms create such strong Faraday rotation.Aims. We investigate the effect of spiral arms on Galactic Faraday rotation through shock compression of the interstellar medium. It has recently been suggested that the Sagittarius spiral arm creates a strong peak in Faraday rotation where the line of sight is tangent to the arm, and that enhanced Faraday rotation follows along side lines which intersect the arm. Here, we seek to understand the physical conditions that may give rise to this effect and the role of viewing geometry.Methods. We apply a magnetohydrodynamic simulation of the multi-phase interstellar medium in a Milky Way type spiral galaxy disk in combination with radiative transfer in order to evaluate different tracers of spiral arm structures. For observers embedded in the disk, dust intensity, synchrotron emission and the kinematics of molecular gas observations are derived to identify which spiral arm tangents are observable. Faraday rotation measures are calculated through the disk and evaluated in the context of different observer positions. The observer’s perspectives are related to the parameters of the local bubble surrounding the observer and their contribution to the total Faraday rotation measure along the line of sight.Results. We reproduce a scattering of tangent points for the different tracers of about 6° per spiral arm similar to the Milky Way. As for the RM, the model shows that compression of the interstellar medium and associated amplification of the magnetic field in spiral arms enhances Faraday rotation by a few hundred rad m¯2 on top of the mean contribution of the disk. The arm-inter-arm contrast in Faraday rotation per unit distance along the line of sight is approximately ∼ 10 in the inner Galaxy, fading to ∼ 2 in the outer Galaxy in tandem with the waning contrast of other tracers of spiral arms. We identify a shark-fin like pattern in the RM Milky Way observations as well as the synthetic data that is characteristic for a galaxy with spiral arms
Recruitment and retention of older adults in Assisted Living Facilities to a clinical trial using technology for falls prevention: A qualitative case study of barriers and facilitators
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Dynamic Coordination of Miscible Polymer Blends towards Highly Designable Shape Memory Effect
No full textMiscible polymer blends offer great designability on shape memory effect (SME) with adjustable mechanical properties and stimuli-responsiveness, by simply changing the constituent compositions. However, the thermodynamics understanding behind those SMEs on miscible polymer blends are yet to be explored. This paper describes an approach to achieve highly designable SMEs with adjustable glass transition temperature (Tg) and width of glass transition zone by dynamically coordinating components in miscible blends. An extended domain size model was formulated based on the Adam-Gibbs theory and Gaussian distribution theory to study the synergistic coordination of component heterogeneities on conformational entropy, glass transition and relaxation behaviour of the miscible blend. The effectiveness of model was demonstrated by applying it to predict dual- and triple-SMEs in miscible polymer blends, where the theoretical results show good agreements with the experiment results. We expect this study provide an effective guidance on designing advanced miscible polymer blends based on the SME
Fully Distributed Affine Formation Control of General Linear Systems with Uncertainty
No full textThis paper considers the distributed affine formation control problem of general linear systems with uncertainty. In affine formation manoeuvre control, the agents are to be capable of producing specified geometric patterns and simultaneously accomplish required manoeuvres, such as scales, translations and rotations. Here, the formation control problem is studied using the stress matrix approach which has similar properties as the Laplacian matrix of a graph, with a major difference being that the edge weights can have positive or negative values. The system stability is analysed using Lyapunov theory. Novel affine formation control laws for general linear systems are presented. Four control laws are presented to address different cases. The proposed laws consider the general linear case, the case with uncertainty and the fully distributed case using robust and adaptive strategies. Under the proposed laws, the collection of agents can track any targets that are affine transforms of a defined reference configuration. Experimental results are presented to demonstrate the effectiveness of the proposed control laws
Ferulic acid decarboxylase (Fdc1) controls oxidative maturation of the prFMN cofactor
No full textPrenylated FMN (prFMN) is a recently discovered modified flavin cofactor containing an additional non-aromatic ring, connected to the N5 and C6 atoms. This cofactor underpins reversible decarboxylation catalyzed by members of the widespread UbiD-enzyme family, and is produced by the flavin prenyltransferase UbiX. Oxidative maturation of the UbiX product prFMNH2 to the corresponding oxidized prFMNiminium is required for Fdc1 (a UbiD-type enzyme) activity. However, it is unclear what role the Fdc1-enzyme plays in this process. Here we demonstrate that in the absence of Fdc1, prFMNH2 oxidation by O2 proceeds via a transient semiquinone prFMNradical species and culminates in a remarkably stable prFMN-hydroperoxide species. Neither forms of prFMN are able to support Fdc1 activity. Instead, enzyme activation using O2-mediated oxidation requires prFMNH2 binding prior to oxygen exposure, confirming that UbiD-enzymes play a role in O2 mediated oxidative maturation. In marked contrast, alternative oxidants such as potassium ferricyanide support prFMNiminium formation both in solution and in Fdc1
A process-focused case series of a school-based intervention aimed at giving young people choice and control over their attendance and their goals in therapy
No full textThis study investigated clinical and process factors involved in a client-led psychological intervention (Method of Levels therapy- MOL). MOL offered 16 adolescents choice and control over attendance (by using a self-booking system) and topics discussed in sessions. Process measures examining empowerment and ability to resolve psychological conflict were used to explore the impact MOL might have on these. Young people booked a wide-ranging number of sessions at differing intervals and set goals related to their emotional or mental wellbeing. On completion, the majority of adolescents displayed an increase in scores for empowerment and ability to resolve psychological conflict and overall distress levels decreased. Benefits were sustained two months after completion of the study
Accounting for Institutional Work: A Critical Review
No full textThis paper offers a review of a rapidly growing body of accounting research, using the concept of institutional work, with an eye to whether and how it has addressed key criticisms levied at this strand of institutional theory. Four sets of criticism of the institutional work perspective, pivoting on its emphasis on such work as an institutionally embedded multi-level phenomenon, the intentions behind institutional work, the relationship between habitual and reflexive agency and its conception of power, are identified. Insofar as accounting research using the concept of institutional work has addressed such criticisms, it has mainly been confined to those emerging within institutional theory whilst much less attention has been paid to criticisms raised by critical management scholars who are less sympathetic to institutional theory. Drawing on recent advances in critical sociology, I advance a framework that addresses these criticisms. In doing so, I discuss the possibilities of imbuing research on institutional work with innate concerns with radical social critique and emancipation. This contributes to a refined understanding of institutional work as a source of change and stability and provides a platform for turning institutional accounting research into a politically engaged research programme underpinned by critical intent
Supervised classification of bradykinesia in Parkinson’s disease from smartphone videos
No full textBackground: Slowness of movement, known as bradykinesia, is the core clinical sign of Parkinson’s and fundamental to its diagnosis. Clinicians commonly assess bradykinesia by making a visual judgement of the patient tapping finger and thumb together repetitively. However, inter-rater agreement of expert assessments has been shown to be only moderate, at best.Aim: We propose a low-cost, contactless system using smartphone videos to automatically determine the presence of bradykinesia.Methods: We collected 70 videos of finger-tap assessments in a clinical setting (40 Parkinson’s hands, 30 control hands). Two clinical experts in Parkinson’s, blinded to the diagnosis, evaluated the videos to give a grade of bradykinesia severity between 0 and 4 using the Unified Pakinson’s Disease RatingScale (UPDRS). We developed a computer vision approach that identifies regions related to hand motion and extracts clinically-relevant features. Dimensionality reduction was undertaken using principal component analysis before inputto classification models (Na¨ıve Bayes, Logistic Regression, Support Vector Machine) to predict no/slight bradykinesia (UPDRS=0-1) or mild/moderate/severe bradykinesia (UPDRS = 2-4), and presence or absence of Parkinson’s diagnosis.Results: A Support Vector Machine with radial basis function kernels predicted presence of mild/moderate/severe bradykinesia with an estimated test accuracy of 0.8. A Na¨ıve Bayes model predicted the presence of Parkinson’s diseasewith estimated test accuracy 0.67.Conclusion: The method described here presents an approach for predicting bradykinesia from videos of fingertapping tests. The method is robust to lighting conditions and camera positioning. On a set of pilot data, accuracy of bradykinesia prediction is comparable to that recorded by blinded human experts