1,720,972 research outputs found
Sulla presenza del coleottero scolitide Dendroctonus micans Kugelann in boschi di abete rosso del Veneto.
No full textTrephor: A new tool for sampling microcores from tree stems
No full textDetailed analyses of cambium activity and wood formation during growth need repeated sampling of newly formed xylem. In order to be minimally invasive, wood samples are extracted as rnicrocores. Despite the research done on xylem cell development and the increasing interest in intra-annual studies of xylogenesis, few tools are available for microcore sampling. Methods originally designed for other purposes have often been used, but no details are available on their efficiency and usefulness. Information is also lacking on laboratory preparation techniques for cell analysis of tree-ring formation, leading to difficulties in carrying out these experiments. The advantages and limits of the tools used up to now are described. A new tool, named Trephor (patent pending n degrees PD2004A000324), specifically designed for long-lasting use is presented. Trephor is chisel-shaped for a fast recovery of 2 mm diameter microcores. The cutting tube is inserted into the wood using a hammer and no other accessory is required. Simple technical characteristics allow high quality samples to be collected from both softwood and hardwood species with minimum damage to the sampled trees. Trephor was tested during the 2004 growing season, demonstrating good resistance to wear and tear and mechanical stress. Embedding the microcores in paraffin for fast section preparation is described
Il laghetto delle Sepolture nell’area del Pian dei Buoi (Lozzo di Cadore, BL): monitoraggio idrometrico e della biodiversità: primi interventi di ripristino
No full textIl Laghetto delle Sepolture è l’unico specchio d’acqua di ambiente palustre rimasto nel Pian dei Buoi e in tutto il gruppo montuoso Marmarole – Antelao – Sorapiss. Parzialmente occluso dalla vegeta- zione, è stato recentemente danneggiato da significativi eventi di calpestio da parte di bovini. Per definire una strategia di tutela, è stato installato un sistema di monitoraggio dell’altezza idrometrica e sono state realizzate delle indagini sulle componenti biotiche. I primi risultati mostrano che il livello idrometrico è estremamente dinamico: in genere, diminuisce di 1,1 mm ogni ora, ma aumenta velocemente in occasione di eventi piovosi. Le componenti faunistiche e floristiche sono risultate estremamente impoverite: l’unica valenza residua sembra una cospicua popolazione di tritone alpestre. Per rallentare la scomparsa dell’ha- bitat e riqualificarlo, sono stati realizzati alcuni semplici interventi, tra cui la posa di una recinzione per il pascolo e lo sfalcio di una parte della vegetazione
Campionatore Trephor: un nuovo strumento per l'analisi della xilogenesi in specie legnose
No full text
Going 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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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