High-resolution Elemental Mapping of the Lunar Surface

New instruments and missions are being proposed to study the lunar surface as a result of the resurgence of interest in returning to the Moon. One instrument recently proposed is similar in concept to the x-ray fluorescence detectors flown on Apollo, but utilizes fluorescence from the L- and M-shells rather than the K-shell. This soft X-Ray Flourescence Imager (XRFI) is discussed

Symplectic integrators for classical spin systems

We suggest a numerical integration procedure for solving the equations of motion of certain classical spin systems which preserves the underlying symplectic structure of the phase space. Such symplectic integrators have been successfully utilized for other Hamiltonian systems, e. g. for molecular dynamics or non-linear wave equations. Our procedure rests on a decomposition of the spin Hamiltonian into a sum of two completely integrable Hamiltonians and on the corresponding Lie-Trotter decomposition of the time evolution operator. In order to make this method widely applicable we provide a large class of integrable spin systems whose time evolution consists of a sequence of rotations about fixed axes. We test the proposed symplectic integrator for small spin systems, including the model of a recently synthesized magnetic molecule, and compare the results for variants of different order

Do Clinical Ethicists Improve with Experience? And, If So, How Would We Know?

Lors de l’atelier organisé dans le cadre de l’atelier et du forum communautaire 2023 de la SCB-SCB, nous avons exploré et problématisé le concept d’ « amélioration » des éthiciens cliniques, dans le contexte plus large des discussions sur la professionnalisation de l’éthique clinique. Ce résumé présente les principaux points de vue d’éthiciens cliniques à travers le Canada sur ce sujet et comprend des suggestions sur les mesures que nous pourrions prendre sur le terrain pour permettre et soutenir l’amélioration des éthiciens cliniques à l’avenir.During our workshop at the 2023 CBS-SCB Workshop and Community Forum, we explored and problematized the concept of “improvement” of clinical ethicists, situated within the larger context of discussions about the professionalization of clinical ethics. This summary provides key insights on this topic by clinical ethicists from across Canada and includes suggestions for steps that we might want to take in the field to enable and support the improvement of clinical ethicists going forward

Synthesis of Planar Rigid-Body Mechanisms Approximating Shape Changes Defined by Closed Curves

This paper presents a procedure to synthesize planar linkages, composed of rigid links and revolute joints, that are capable of approximating a shape change defined by a set of closed curves possessing similar arc lengths. The synthesis approach is more rigorous and more broadly applicable to dramatic changes between larger numbers of shapes than existing techniques that employ graphical methods. It specifically addresses the challenges of approximating closed curves, but the methodology is equally applicable to open curves. Link geometry is determined through an existing procedure, and those links are then joined together in a chain using numerical optimization to minimize the error in approximating the shape change. Binary links are added to this chain via a search of the design space, forming a single-degree-of-freedom mechanism in which an actuated link can be driven monotonically to exact the shape change. The procedure is applied to synthesize an example mechanism that changes between circular, elliptical, and teardrop shapes as inspired by an aerodynamic flow field modification application