1,721,112 research outputs found
How does climate influence xylem morphogenesis over the growing season? Insights from long-term intra-ring anatomy in Picea abies
No full textDuring the growing season, the cambium of conifer trees produces successive rows of xylem cells, the tracheids, that sequentially pass through the phases of enlargement and secondary wall thickening before dying and becoming functional. Climate variability can strongly influence the kinetics of morphogenetic processes, eventually affecting tracheid shape and size. This study investigates xylem anatomical structure in the stem of Picea abies to retrospectively infer how, in the long term, climate affects the processes of cell enlargement and wall thickening
Wood anatomical responses to long-term enrichment and soil warming in Larix decidua treeline trees
No full textAnatomical responses to long-term co2 enrichment and soil warming in Larix decidua trees at the alpine treeline
No full textConduit-size based comparison of present and past tree height growth rates at two treeline sites in the Alps
No full textSplitting the ring: Cell Anatomy unravels intra-seasonal climate influence on xylogenesis over long-time periods
No full textXylogenesis of compression and opposite wood in mountain pine at a Mediterranean treeline
No full textInternational audienceAbstractKey messageComparisons between compression and opposite wood formation in prostratingPinus mugoindicate that the secondary meristem can produce more tracheids with thicker walls by also increasing the number of contemporaneously differentiating cells, rather than only increasing the duration or the rate of cell formation.ContextAlthough cambium tissues within a stem experience the same climatic conditions, the resulting wood structure and properties can strongly differ. Assessing how meristem differently regulates wood formation to achieve different anatomical properties can help understanding the mechanisms of response and their plasticity.AimsWe monitored the formation of compression (CW) and opposite (OW) wood within the same stems to understand whether achieved differences in wood structure are caused by modifications in the process of cell formation.MethodsWe collected weekly microcores of compression and opposite wood from the curved stem of ten treeline prostrating mountain pines (Pinus mugo Turra ssp. mugo) at the Majella massif in Central Italy.ResultsResults indicate that cambium formed approximately 1.5 times more cells in CW than OW, despite that CW cell differentiation only extended 2 weeks longer and the residence time of CW cells in the wall-thickening phase was only 20% longer. Differences in their formation were thus mainly related to both the rates and the width of the enlarging and wall-thickening zones (i.e., the number of cells simultaneously under differentiation) and less to duration of cell formation.ConclusionWe conclude that to achieve such a different wood structures, the efficiency of the secondary meristem, in addition of altered rate of cell division and differentiation, can also modify the width of the developing zones. Thus, deciphering what rules this width is important to link environmental conditions with productivity
Xylem anatomy supplies a mechanistic explanation behind tree-growth release during a long term FACE experiment at the Swiss Treeline
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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