The Genesis of Magnetic Fields in White Dwarfs

Magnetic fields generated by a dynamo mechanism due to differential rotation during stellar mergers are often proposed as an explanation for the presence of strong fields in certain classes of magnetic stars, including high field magnetic white dwarfs (HFMWDs). In the case of the HFMWDs, the site of the differential rotation has been variously proposed to be the common envelope itself, the massive hot outer regions of a merged degenerate core or an accretion disc formed by a tidally disrupted companion that is subsequently incorporated into a degenerate core. In the present study I explore the possibility that the origin of HFMWDs is consistent with stellar interactions during the common envelope evolution (CEE). In this picture the observed fields are caused by an alpha-Omega dynamo driven by differential rotation. The strongest fields would arise when the differential rotation equals the critical break up velocity and would occur from the merging of two stars during CEE or double degenerate (DD) mergers in a post common envelope (CE) stage. Those systems that do not coalesce but emerge from the CE on a close orbit and about to initiate mass transfer will evolve into magnetic cataclysmic variables (MCVs). The population synthesis calculations carried out in this work have shown that the origin of high fields in isolated white dwarfs (WDs) and in WDs in MCVs is consistent with stellar interaction during common envelope evolution. I compare the calculated field strengths to those observed and test the correlation between theory and observation by means of the Kolmogorov–Smirnov (K–S) test and show that the resulting correlation is good for values of the CE energy efficiency parameter, ALPHA-CE, in the range 0.1–0.3

The Poisson-Boltzmann model for implicit solvation of electrolyte solutions: Quantum chemical implementation and assessment via Sechenov coefficients.

We present the theory and implementation of a Poisson-Boltzmann implicit solvation model for electrolyte solutions. This model can be combined with arbitrary electronic structure methods that provide an accurate charge density of the solute. A hierarchy of approximations for this model includes a linear approximation for weak electrostatic potentials, finite size of the mobile electrolyte ions, and a Stern-layer correction. Recasting the Poisson-Boltzmann equations into Euler-Lagrange equations then significantly simplifies the derivation of the free energy of solvation for these approximate models. The parameters of the model are either fit directly to experimental observables-e.g., the finite ion size-or optimized for agreement with experimental results. Experimental data for this optimization are available in the form of Sechenov coefficients that describe the linear dependence of the salting-out effect of solutes with respect to the electrolyte concentration. In the final part, we rationalize the qualitative disagreement of the finite ion size modification to the Poisson-Boltzmann model with experimental observations by taking into account the electrolyte concentration dependence of the Stern layer. A route toward a revised model that captures the experimental observations while including the finite ion size effects is then outlined. This implementation paves the way for the study of electrochemical and electrocatalytic processes of molecules and cluster models with accurate electronic structure methods

ICRA Roboethics Challenge 2023: Intelligent Disobedience in an Elderly Care Home

With the projected surge in the elderly population, service robots offer a promising avenue to enhance their well-being in elderly care homes. Such robots will encounter complex scenarios which will require them to perform decisions with ethical consequences. In this report, we propose to leverage the Intelligent Disobedience framework in order to give the robot the ability to perform a deliberation process over decisions with potential ethical implications. We list the issues that this framework can assist with, define it formally in the context of the specific elderly care home scenario, and delineate the requirements for implementing an intelligently disobeying robot. We conclude this report with some critical analysis and suggestions for future work.Comment: This report is part of ICRA roboethics competition : https://competition.raiselab.ca/competition-details-2023_1/ethics-challenge/submitted-proposals/submission-

Sidechain control of porosity closure in multiple peptide-based porous materials by cooperative folding

Porous materials find application in separation, storage and catalysis. We report a crystalline porous solid formed by coordination of metal centres with a glycylserine dipeptide. We prove experimentally that the structure evolves from a solvated porous into a non-porous state as result of ordered displacive and conformational changes of the peptide that suppress the void space in response to environmental pressure. This cooperative closure, which recalls the folding of proteins, retains order in three-dimensions and is driven by the hydroxyl groups acting as H-bond donors in the peptide sequence through the serine residue. This ordered closure is also displayed by multipeptide solid solutions in which the combination of different sequences of amino acids controls their guest response in a non-linear way. This functional control can be compared to the effect of single point mutations in proteins, where the exchange of single amino acids can radically alter structure and functio

Advancing the Provision of Pain Education and Learning (APPEAL) study

Objectives Unrelieved pain is a substantial public health concern necessitating improvements in medical education. The Advancing the Provision of Pain Education and Learning (APPEAL) study aimed to determine current levels and methods of undergraduate pain medicine education in Europe. Design and methods Using a cross-sectional design, publicly available curriculum information was sought from all medical schools in 15 representative European countries in 2012–2013. Descriptive analyses were performed on: the provision of pain teaching in dedicated pain modules, other modules or within the broader curriculum; whether pain teaching was compulsory or elective; the number of hours/credits spent teaching pain; pain topics; and teaching and assessment methods. Results Curriculum elements were publicly available from 242 of 249 identified schools (97%). In 55% (133/242) of schools, pain was taught only within compulsory non-pain-specific modules. The next most common approaches were for pain teaching to be provided wholly or in part via a dedicated pain module (74/242; 31%) or via a vertical or integrated approach to teaching through the broader curriculum, rather than within any specific module (17/242; 7%). The curricula of 17/242 schools (7%) showed no evidence of any pain teaching. Dedicated pain modules were most common in France (27/31 schools; 87%). Excluding France, only 22% (47/211 schools) provided a dedicated pain module and in only 9% (18/211) was this compulsory. Overall, the median number of hours spent teaching pain was 12.0 (range 4–56.0 h; IQR: 12.0) for compulsory dedicated pain modules and 9.0 (range 1.0–60.0 h; IQR: 10.5) for other compulsory (non-pain specific) modules. Pain medicine was principally taught in classrooms and assessed by conventional examinations. There was substantial international variation throughout. Conclusions Documented pain teaching in many European medical schools falls far short of what might be expected given the prevalence and public health burden of pain

Why geriatric medicine? A survey of UK specialist trainees in geriatric medicine

Background: There is global concern that there are insufficient numbers of geriatricians to meet the needs of the ageing population. A 2005 survey described factors that influenced why UK geriatricians had chosen to specialise in the field - in the decade since, UK postgraduate training has undergone a fundamental restructure. Objective: To explore whether the reasons for choosing a career in geriatric medicine in the UK had changed over time, with the goal of using this knowledge to inform recruitment and training initiatives. Design: An online survey was sent to all UK higher medical trainees in geriatric medicine. Methods: Survey questions that produced categorical data were analysed with simple descriptive statistics. For the survey questions that produced free-text responses, an inductive, iterative approach to analysis, in keeping with the principles of framework analysis, was employed. Results: 269 responses were received out of 641 eligible respondents. Compared with the previous survey, a substantially larger number of respondents regarded geriatric medicine to be their first-choice specialty and a smaller number regretted their career decision. A greater number chose geriatric medicine early in their medical careers. Commitments to the general medical rota and the burden of service provision were considered important downsides to the specialty. Conclusions: There are reasons to be optimistic about recruitment to geriatric medicine. Future attempts to drive up recruitment might legitimately focus on the role of the medical registrar and perceptions that geriatricians shoulder a disproportionate burden of service commitments and obligations to the acute medical take

Use of a Distal Radius Endoprosthesis Following Resection of a Bone Tumour: A Case Report

Limited literature is available on the reconstruction of the distal radius using prosthetic replacement following resection of a bone tumour. We present the first reported case, in the English literature, of the use of an entirely metal endoprosthesis for the reconstruction of the distal radius. This case involves a 66-year-old male who was treated for giant cell tumour of the distal radius with surgical excision of the lesion and replacement of the defect using a predominantly titanium endoprosthesis. He was followed-up for 56 months following surgery and had a good functional outcome with no associated pain or complications. We propose that the use of a primarily titanium endoprosthesis for the reconstruction of a bone defect of the distal radius is a suitable alternative, providing good function of the forearm with satisfactory range of movement at the wrist and adequate pain relief