The Corps of Guides, 1903–1914

The Canadian Corps of Guides was created in April 1903 by General Order 61, and fell under the purview of the Intelligence Department at Militia Headquarters in Ottawa. However, as the Guides were a service of the Active Militia, and not of the Permanent Force, they were not a full-time formation. The Corps was designed to fulfil both a peacetime and wartime role. During active operations it was to act as a combat intelligence force for Canadian armies in the field, and provide commanders with operational and tactical level intelligence. During peacetime it was to prepare for this eventuality, but more importantly, it was to help accumulate intelligence on Canada’s military resources and capabilities, as well as on those of foreign powers, in particular the United States. As with all of Canada’s peacetime military establishments, the Guides suffered from underfunding, understaffing and undertraining. Nevertheless, the Corps of Guides was still able to provide a valuable service in the years leading up to the First World War, and offered its members a background in Intelligence that would prove indispensable in that war

Structure and formation energy of carbon nanotube caps

We present a detailed study of the geometry, structure and energetics of carbon nanotube caps. We show that the structure of a cap uniquely determines the chirality of the nanotube that can be attached to it. The structure of the cap is specified in a geometrical way by defining the position of six pentagons on a hexagonal lattice. Moving one (or more) pentagons systematically creates caps for other nanotube chiralities. For the example of the (10,0) tube we study the formation energy of different nanotube caps using ab-initio calculations. The caps with isolated pentagons have an average formation energy 0.29+/-0.01eV/atom. A pair of adjacent pentagons requires a much larger formation energy of 1.5eV. We show that the formation energy of adjacent pentagon pairs explains the diameter distribution in small-diameter nanotube samples grown by chemical vapor deposition.Comment: 8 pages, 8 figures (gray scale only due to space); submitted to Phys. Rev.

The Betteshanger Summer School: Missing link between biodynamic agriculture and organic farming

Biodynamic agriculture and organic farming have been regarded as having different provenances and having arisen independently. The present account introduces the ‘missing link’ between the two. In 1938 Ehrenfried Pfeiffer published the milestone book on biodynamics: Bio-Dynamic Farming and Gardening. In 1940 Lord Northbourne published Look to the Land, the work that introduced the term ‘organic farming’. In the summer of the intervening year, Pfeiffer travelled from Switzerland to Northbourne’s estate in Kent, UK, and presented for British farmers a nine day course on biodynamics, the Betteshanger Summer School and Conference on Bio-Dynamic Farming, 1-9 July 1939. Pfeiffer was supported by the pre-eminent biodynamic scholar-practitioners, Otto Eckstein and Hans Heinze. Dr Scott Williamson of the Peckham Experiment was the sole British lecturer at the Betteshanger Summer School. For the UK Bio-Dynamic Association, the Betteshanger Summer School was the highlight of the year. Northbourne and Pfeiffer had collaborated on the Farleigh Experiment in 1938, and Northbourne had travelled to Switzerland in January 1939 to arrange Pfeiffer’s visit. War broke out less than eight weeks after the Betteshanger Summer School. Northbourne’s manifesto on organic agriculture, Look to the Land, was published in May of the following year. The book took the Steinerian and biodynamic view of ‘the farm as an organism’ as its central tenet and adopted it as the nominative motif for ‘organic’ farming. The book offered to the Anglophone world an account that was secular and distanced from any Anthroposophic or Germanic roots. Subsequently, Northbourne sought to bring Pfeiffer to the UK but Pfeiffer’s next and final visit was in 1950. The Betteshanger Summer School and Conference on biodynamics has been otherwise unreported. As this account demonstrates, Betteshanger was a stepping stone from biodynamics to organics. Northbourne sponsored Pfeiffer’s visit and the Betteshanger biodynamics conference in 1939, and the following year he introduced his term ‘organic farming’ and its philosophy in his book Look to the Land

Spectral-based Propagation Schemes for Time-Dependent Quantum Systems with Application to Carbon Nanotubes

Effective modeling and numerical spectral-based propagation schemes are proposed for addressing the challenges in time-dependent quantum simulations of systems ranging from atoms, molecules, and nanostructures to emerging nanoelectronic devices. While time-dependent Hamiltonian problems can be formally solved by propagating the solutions along tiny simulation time steps, a direct numerical treatment is often considered too computationally demanding. In this paper, however, we propose to go beyond these limitations by introducing high-performance numerical propagation schemes to compute the solution of the time-ordered evolution operator. In addition to the direct Hamiltonian diagonalizations that can be efficiently performed using the new eigenvalue solver FEAST, we have designed a Gaussian propagation scheme and a basis transformed propagation scheme (BTPS) which allow to reduce considerably the simulation times needed by time intervals. It is outlined that BTPS offers the best computational efficiency allowing new perspectives in time-dependent simulations. Finally, these numerical schemes are applied to study the AC response of a (5,5) carbon nanotube within a 3D real-space mesh framework

Virtual space and 2-dimensional effects in perspective displays

When interpreting three dimensional spatial relationships presented on a two dimensional display surface, the viewer is required to mentally reconstruct the original information. This reconstruction is influenced by both the perspective geometry of the displayed image and the viewer's eye position relative to the display. In a study which manipulated these variables, subjects judged the azimuth direction of a target object relative to a reference object fixed in the center of a perspective display. The results support a previously developed model which predicted that the azimuth judgement error would be a sinusoidal function of stimulus azimuth. The amplitude of this function was correctly predicted to be systematically modulated by both the perspective geometry of the image and the viewer's eye position relative to the screen. Interaction of the two components of the model, the virtual space effect and the 3D-to-2D projection effect, predicted the relative amplitudes of the sinusoidal azimuth error functions for the various conditions of the experiment. Mean azimuth judgements in some directions differed by as much as 25 degrees as a result of different combinations of eye position and image geometry. The results illustrate the need to consider the effects of perspective geometry when designing spatial information instruments, and show the model to be a reliable predictor of average performance

Identification of the catalytic motif of the microbial ribosome inactivating cytotoxin colicin E3

Colicin E3 is a cytotoxic ribonuclease that specifically cleaves 16S rRNA at the ribosomal A-site to abolish protein synthesis in sensitive Escherichia coli cells. We have performed extensive mutagenesis of the 96-residue colicin E3 cytotoxic domain (E3 rRNase), assayed mutant colicins for in vivo cytotoxicity, and tested the corresponding E3 rRNase domains for their ability to inactivate ribosome function in vitro. From 21 alanine mutants, we identified five positions where mutation resulted in a colicin with no measurable cytotoxicity (Y52, D55, H58, E62, and Y64) and four positions (R40, R42, E60, and R90) where mutation caused a significant reduction in cytotoxicity. Mutations that were found to have large in vivo and in vitro effects were tested for structural integrity through circular dichroism and fluorescence spectroscopy using purified rRNase domains. Our data indicate that H58 and E62 likely act as the acid–base pair during catalysis with other residues likely involved in transition state stabilization. Both the Y52 and Y64 mutants were found to be highly destabilized and this is the likely origin of the loss of their cytotoxicity. The identification of important active site residues and sequence alignments of known rRNase homologs has allowed us to identify other proteins containing the putative rRNase active site motif. Proteins that contained this active site motif included three hemagglutinin-type adhesins and we speculate that these have evolved to deliver a cytotoxic rRNase into eukaryotic cells during pathogenesis

Mortality in the Caucasus

With the collapse of the Soviet Union, Caucasian countries experienced remarkable migration flows, political conflicts, and deterioration of civil registration systems. The reassessment of Armenian and Georgian population after censuses carried out in the early 2000s enables to re-estimate recent mortality levels in both countries. Vital statistics since the 1980s are presented and discussed. Infant mortality is corrected according to sample surveys, and mortality above age 60 estimated through model life tables. On the basis of these estimates, trends in life expectancy were similar in the two countries, unfavourable during the 1990s, especially for males for whom the health progress, notably in Georgia, is still low.administrative data, Armenia, estimation, Georgia, life expectancy, mortality, reliability, survey data