Historical Records and Relics from the North Greenland Coast

Reports recovery of nine records during geological reconnaissance by the Danish party of Operation Grant Land 1966, organized by the Geological Survey of Canada. The oldest is an 1876 copy of a record from 1871, the youngest dates from 1921. Records and relics from the US North Polar Expedition, 1871-73, British Arctic Expedition, 1875-76, US Lady Franklin Bay Expedition, 1881-84, Danish 2nd Thule Expedition, 1916-18, and Danish Bicentenary Jubilee Expedition, 1920-23, are included.Documents et historiques de la côte nord du Groënland. L'auteur rapporte la découverte récente, sur la côte peu fréquentée du nord du Groënland, de neuf documents historiques et de vestiges qui leur sont associés. Le matériel provient de cinq expéditions arctiques de la fin du 19e siècle et du début du 20e, dans la région du chenal de Robeson. On a reproduit en facsimilé des pages de deux de ces documents.&nbsp

Pressure Shifts in High-Precision Hydrogen Spectroscopy: I. Long-Range Atom-Atom and Atom-Molecule Interactions

We study the theoretical foundations for the pressure shifts in high-precision atomic beam spectrosopy of hydrogen, with a particular emphasis on transitions involving higher excited P states. In particular, the long-range interaction of an excited hydrogen atom in a 4P state with a ground-state and metastable hydrogen atom is studied, with a full resolution of the hyperfine structure. It is found that the full inclusion of the 4P_1/2 and 4P_3/2 manifolds becomes necessary in order to obtain reliable theoretical predictions, because the 1S ground state hyperfine frequency is commensurate with the 4P fine-structure splitting. An even more complex problem is encountered in the case of the 4P-2S interaction, where the inclusion of quasi-degenerate 4S-2P_1/2 state becomes necessary in view of the dipole couplings induced by the van der Waals Hamiltonian. Matrices of dimension up to 40 have to be treated despite all efforts to reduce the problem to irreducible submanifolds within the quasi-degenerate basis. We focus on the phenomenologically important second-order van der Waals shifts, proportional to 1/R^6 where R is the interatomic distance, and obtain results with full resolution of the hyperfine structure. The magnitude of van der Waals coefficients for hydrogen atom-atom collisions involving excited P states is drastically enhanced due to energetic quasi-degeneracy; we find no such enhancement for atom-molecule collisions involving atomic nP states, even if the complex molecular spectrum involving ro-vibrational levels requires a deeper analysis.Comment: 32 pages; 2 figures; this is part 1 of a series of two papers; part 1 carries article number 075005, while part 2 carries article number 075006 in the journal (online journal version has been rectified). arXiv admin note: text overlap with arXiv:1711.1003

Why I became a chemistry teacher: identifying turning points in chemistry teacher narratives of their trajectories into teaching

BACKGROUND: Currently there are international concerns over teacher recruitment and attrition rates, especially in mathematics and the physical sciences. Much has been written about the recruitment of student teachers and the reasons people give for going into teaching, but little on the broader context of these people’s lives and the complex influences on their career decisions. PURPOSE: The narrative approach used in this study is a complement to larger scale quantitative studies into teacher recruitment as it seeks to consider the wider picture of a person’s life and, through a defended participant perspective, expose influences that may not have been obvious to the participants themselves. Sample: Eight current UK chemistry teachers. SAMPLE: Eight current UK chemistry teachers. DESIGN AND METHODS: Stories of becoming teachers are told through interviews and these narratives examined to consider the key influences upon their becoming chemistry teachers. Two analytic lenses were used: inductive thematic analysis and deductive analysis considering psychoanalytical defences. These lenses were used to both exemplify and challenge each other, providing triangulation of interpretation to determine participants’ trajectories into chemistry teaching. RESULTS: Family background and interest in, and utility of, studying chemistry were found to influence career life decisions. Some participants experienced moments where their career trajectory changed towards teaching whereas others followed a smooth path towards this end. For two, changes in their relationship with chemistry resulted in a teaching career. Particularly influential appears to be prior teaching experience which led to changes of trajectory for half of the participants in this study. CONCLUSION: The chemistry teachers’ relationship with the subject discipline and prior teaching experience were important in them entering the profession, whilst the influence of their own teachers is more nuanced than wider larger scale quantitative studies suggest. Findings suggest that increasing the opportunity for classroom experience for undergraduates may improve teacher recruitment