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Editors' Note / Note de la rédaction

I write my last editor’s note feeling a mixture of relief and sentimentality. It was before Christmas in 2006 when the military historian, Jean Martin, at the Department of National Defence, approached my branch at Parks Canada, looking for someone enthusiastic to replace John Willis as the English-language secretary. Jean and I had represented our respective organizations on the inter-departmental heritage review committee that assigns heritage scores to federal buildings over 40 years in age, and from that experience I knew he would be easy to work with. Moreover, I had great respect for the CHA and fond memories of attending conferences over the years.With little arm-twisting, I concluded that this was a worthy cause and I put my name into the hat.About six months later I was meeting with Jean and John in one of the boardrooms of the Canadian Museum of Civilization. I had no idea what the next few years would yield, and no crystal ball to tell me that the CHA was on the cusp of a major transformation

Profil - Lyle Dick , Vice-président de la SHC

Lyle Dick est l’auteur de 90 publications traitant de l’histoire canadienne et américaine, l’historiographie et l’histoire de l’arctique, y compris le livre Muskox Land: Ellesmere Island in the Age of Contact (University of Calgary Press, 2001), qui a reçu le prix Harold Adams Innis pour le meilleur ouvrage de langue anglaise en sciences humaines en 2003 et Farmers « Making Good » (Édition revue et corrigée, University of Calgary Press,2008), co-lauréat du prix Clio de la Société historique du Canada en 1990 pour le meilleur livre sur l’histoire des provinces des prairies

Profile - Lyle Dick CHA Vice-President

Lyle Dick is the author of 90 publications on topics in Canadian and American history, historiography, and Arctic history, including the book Muskox Land: Ellesmere Island in the Age of Contact(University of Calgary Press, 2001), which was awarded the Harold Adams Innis Prize for Canada’s best-English-language book in the social sciences in 2003, and Farmers “Making Good”(Revised edition, University of Calgary Press, 2008), co-awarded the Canadian Historical Association’s Clio Prize in 1990 for the best book on the history of the prairie provinces

Information for Bulletin contributors

We welcome your submissions to the Bulletin. If you have additional questions about submissions, please do not hesitate to contact the French-language and English-language editors

Bioinspired Breathable Architecture for Water Harvesting

Thuja plicata is a coniferous tree which displays remarkable water channelling properties. In this article, an easily fabricated mesh inspired by the hierarchical macro surface structure of Thuja plicata branchlets is described which emulates this efficient water collection behaviour. The key parameters are shown to be the pore size, pore angle, mesh rotation, tilt angle (branch droop) and layering (branch overlap). Envisaged societal applications include water harvesting and low cost breathable architecture for developing countries

Produção de massa seca e vigor de rebrotação da Brachiaria brizantha cv. Marandu submetida a diferentes doses de nitrogênio e freqüências de cortes

The experiment was disposed in a randomized blocks design, in a factorial scheme, with the objective to evaluate of effect of the nitrogen levels (0, 45, 90, 180 and 360 mg dm-3 of nitrogen - N) and frequencies of harvests (14 and 28 days) under the production of total dry mass and the regrowth vigor of Brachiaria brizantha cv. Marandu, in pots, in a greenhouse, with three repetitions by treatment. All of the variations sources (nitrogen levels, frequencies of harvests and the interactions between them) had effect statistically significative, positive and negative under the production of total dry mass, respectively, for the N levels and the frequencies of harvest. In the study of the regrowth vigor (production harvest-1), the interaction of the harvests and the nitrogen levels were not significative (P<0,01) by the Wilks test. The effect off the nitrogen levels inside of each harvest as much as frequents defoliations, how for less frequents defoliations, provided increment in regrowth vigor with the increase in the supply of N.O experimento foi disposto no delineamento em blocos casualizados, em esquema fatorial, visando avaliar o efeito do nitrogênio (zero, 45, 90, 180 e 360 mg dm-3 de nitrogênio - N) e de freqüências de corte (14 e 28 dias) sobre a produção da massa seca total e o vigor da rebrotação da Brachiaria brizantha cv. Marandu, em vasos, em casa-de-vegetação, com três repetições por tratamento. Todas as fontes de variação (doses de nitrogênio, freqüência de corte e a interação entre eles) tiveram efeito estatisticamente significativo, positivo e negativo sobre a produção de massa seca total, respectivamente, para as doses de N e freqüência de corte. No estudo do vigor de rebrotação (produção corte-1), a interação dos cortes e as doses de nitrogênio não foram significativas (P>;0,01) pelo teste de Wilks. O efeito das doses de nitrogênio dentro de cada corte, tanto para desfolhações freqüentes, como para desfolhações menos freqüentes, proporcionou incremento no vigor de rebrotação, com o aumento do suprimento de N (P<0,01)

Reproductive Ecology and Severe Pollen Limitation in the Polychromic Tundra Plant, Parrya nudicaulis (Brassicaceae)

Pollen limitation is predicted to be particularly severe in tundra habitats. Numerous reproductive patterns associated with alpine and arctic species, particularly mechanisms associated with reproductive assurance, are suggested to be driven by high levels of pollen limitation. We studied the reproductive ecology of Parrya nudicaulis, a species with relatively large sexual reproductive investment and a wide range of floral pigmentation, in tundra habitats in interior montane Alaska to estimate the degree of pollen limitation. The plants are self-compatible and strongly protandrous, setting almost no seed in the absence of pollinators. Supplemental hand pollinations within pollinator exclusion cages indicated no cage effect on seed production. Floral visitation rates were low in both years of study and particularly infrequent in 2010. A diversity of insects visited P. nudicaulis, though syrphid and muscid flies composed the majority of all visits. Pollen-ovule ratios and levels of heterozygosity are consistent with a mixed mating system. Pollen limitation was severe; hand pollinations increased seed production per plant five-fold. Seed-to-ovule ratios remained low following hand pollinations, indicating resource limitation is likely to also be responsible for curtailing seed set. We suggest that pollen limitation in P. nudicaulis may be the result of selection favoring an overproduction of ovules as a bet-hedging strategy in this environmental context of highly variable pollen receipt