Variational integrators, the Newmark scheme, and dissipative systems

Variational methods are a class of symplectic-momentum integrators for ODEs. Using these schemes, it is shown that the classical Newmark algorithm is structure preserving in a non-obvious way, thus explaining the observed numerical behavior. Modifications to variational methods to include forcing and dissipation are also proposed, extending the advantages of structure preserving integrators to non-conservative systems

A Modified Stern-Gerlach Experiment Using a Quantum Two-State Magnetic Field

The Stern-Gerlach experiment has played an important role in our understanding of quantum behavior. We propose and analyze a modified version of this experiment where the magnetic field of the detector is in a quantum superposition, which may be experimentally realized using a superconducting flux qubit. We show that if incident spin-$1/2$ particles couple with the two-state magnetic field, a discrete target distribution results that resembles the distribution in the classical Stern-Gerlach experiment. As an application of the general result, we compute the distribution for a square waveform of the incident fermion. This experimental setup allows us to establish: (1) the quantization of the intrinsic angular momentum of a spin-$1/2$ particle, and (2) a correlation between EPR pairs leading to nonlocality, without necessarily collapsing the particle's spin wavefunction.Comment: 12 pages, 2 figure

Nonsmooth Lagrangian mechanics and variational collision integrators

Variational techniques are used to analyze the problem of rigid-body dynamics with impacts. The theory of smooth Lagrangian mechanics is extended to a nonsmooth context appropriate for collisions, and it is shown in what sense the system is symplectic and satisfies a Noether-style momentum conservation theorem. Discretizations of this nonsmooth mechanics are developed by using the methodology of variational discrete mechanics. This leads to variational integrators which are symplectic-momentum preserving and are consistent with the jump conditions given in the continuous theory. Specific examples of these methods are tested numerically, and the long-time stable energy behavior typical of variational methods is demonstrated

Pandemic pandemonium and primary care networks: Experiences of establishing primary care placements in a new medical school

Background: In 2018 five new medical schools were announced to support the expansion of the workforce. The Kent and Medway programme features early clinical placements in the community. These start in year one, structured as immersion weeks in Primary Care Networks. The KMMS school opened in September 2020 in the midst of the COVID-19 pandemic with all of its attendant challenges. We report on the challenges of selecting and establishing the placements in the newly established primary care networks (PCN). These offer a unique opportunity for medical students to learn about the provision of proactive personalised and co-ordinated multidisciplinary care at an early and formative stage in their careers. Over the course of the first year, multiple adjustments to the learning format were required including a move to blended learning. Summary of Work Initial: challenges included agreeing selection criteria for the PCNs before attending to the legal complexities of contracting and negotiating a service level agreement with the networks, addressing the needs of all stakeholders. Faculty development was conducted remotely. Challenges of the immersion weeks included compromises associated with lockdown restrictions, limited movement across organisations, social distancing and “shielding” students. Over the course of the immersion weeks, we moved to a blended format, navigating the challenges of recorded assessment presentations. Summary of Results: We will present a logic model evaluation of this first year of placements. This summarises the resources required, activities (aspects of implementation) as well as the outcomes. These are considered from the perspective of the school, the GP faculty and students. Discussion and Conclusions: Innovation in establishing a new medical school brings a unique set of challenges to negotiate. PCNs are contractual collaborations between practices (not legal entities), presenting a challenge for both contracting and quality evaluation. COVID-19 constraints compounded the complexities but offered a unique opportunity to observe multidisciplinary, cross organisation work at first hand in the delivery of the COVD vaccination programme. This balanced the change to a blended learning format. Take Home Messages: Flexibility is a key factor in the successful implementation of a new medical school programme involving a range of stakeholders, particularly during a pandemic

Pre-service teachers’ self-efficacy, attitudes and academic performance with regard to undergraduate research modules

The South African schooling system does not sufficiently prepare students for the demands raised by higher education institutions (HEIs). This study investigates the important role that self-efficacy and attitude play in determining pre-service teachers’ performance within research modules at private HEIs. Almost 90% of final year education students (n = 128) at private HEIs, emphasise their dislike for research. They also express their struggle in understanding research modules and how they relate to the teaching profession. This concurrent mixed-method study uses qualitative research to help explain quantitative findings regarding pre-service teachers’ challenges and concerns with regard to research modules. The study also determines pre-service teachers’ self-efficacy and attitude by administering a survey before the module and qualitative questionnaire upon completion of the research module. By determining pre-service teachers’ self-efficacy and attitude, the effectiveness of the research modules is also determined. The relationship between pre-service teachers’ self-efficacy, attitude and research module performance as part of the B.Ed. curriculum is established. The generic nature of undergraduate research modules allows for this case study’s purpose to be transferred to any other discipline or HEI. This study contributes to the advancement of institutional research across HEIs and stimulates interdisciplinary engagement within the field of research modules in South Africa

Coma cluster object populations down to M_R~-9.5

This study follows a recent analysis of the galaxy luminosity functions and colour-magnitude red sequences in the Coma cluster (Adami et al. 2007). We analyze here the distribution of very faint galaxies and globular clusters in an east-west strip of $\sim 42 \times 7$ arcmin$^2$ crossing the Coma cluster center (hereafter the CS strip) down to the unprecedented faint absolute magnitude of M$_R \sim -9.5$. This work is based on deep images obtained at the CFHT with the CFH12K camera in the B, R, and I bands. The analysis shows that the observed properties strongly depend on the environment, and thus on the cluster history. When the CS is divided into four regions, the westernmost region appears poorly populated, while the regions around the brightest galaxies NGC 4874 and NGC 4889 (NGC 4874 and NGC 4889 being masked) are dominated by faint blue galaxies. They show a faint luminosity function slope of -2, very significantly different from the field estimates. Results are discussed in the framework of galaxy destruction (which can explain part of the very faint galaxy population) and of structures infalling on to Coma.Comment: To be published in A&

The History of Poison Gases

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