1,720,972 research outputs found
A NEWLY ESTABLISHED FLUXNET SITE FOR MONITORING ENERGY EXCHANGE AND CARBON BUDGETS OF AGRICULTURAL CROPPING SYSTEMS IN SOUTHERN ITALY.
No full textEffects of water stress on gas exchange of field grown Zea mays L. in Southern Italy: an analysis at canopy and leaf level
No full textZea mays is cultivated in the Mediterranean regions where summer drought may lead to photoinhibition
when irrigation is not available. In this work the response of maize to water stress was evaluated by gas exchange measurements at the canopy and leaf level. Leaf gas exchange was assessed before, during and after water stress, while canopy turbulent fluxes of mass and energy were performed on a continuous basis. In the early growth period, a linear increment of net ecosystem photosynthetic rate
(PNE) to incoming of photosynthetic photon flux density (PPFD) was found and net leaf photosynthetic rate (PNL) showed the tendency to saturate under high irradiance. During water stress, the relationship between PNE and PPFD became curvilinear and both PNE and PNL saturated in a range between 1,000 and 1,500 lmol (photons) m–2 s–1. Leaf water potential (wl) dropped from –1.50 to –1.88 MPa during water stress, indicating that leaf and canopy gas exchanges were limited by stomatal conductance. With the restoration of irrigation, PNE, PNL and wl showed a recovery, and PNE and PNL reached the highest values of whole study period. Leaf area index (LAI) reached a value of 3.0 m2 m–2. The relationship between PNE and PPFD remained curvilinear and PNE values were lower than those of a typical well-irrigated maize crop. The recovery in PNE and PNL after stress, and wl values during stress indicate that
the photosynthetic apparatus was not damaged while soil moisture stress after-effects resulted in a sub-optimal LAI values, which in turn depressed PNE
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Valutazione delle Emissioni di Ammoniaca da Suoli Agricoli in Lombardia : Possibili Approcci
No full textLe più recenti strategie e politiche comunitarie sono sempre più interessate alla divulgazione negli stati membri di tecniche agronomiche e gestionali in grado di limitare gli impatti ambientali del settore agricolo, al fine di accrescere la sostenibilità dell’agroecosistema. L’ obiettivo mira ad una conoscenza più completa della dinamica dell’azoto nei sistemi suolo-pianta-atmosfera e, più in generale, diventare il punto di partenza per azioni di supporto alla pianificazione. Le perdite di azoto a seguito di operazioni di concimazione, in particolare sotto forma di ammoniaca, risultano un problema ambientale e di management sostanziale, soprattutto in regione Lombardia, che si trova a dover gestire elevate quantità di effluenti di allevamento.
Attualmente esistono diverse tecniche di misura sviluppate per determinare gli scambi gassosi, tra le quali sono stati selezionati i metodi che permettono un’effettiva stima dei flussi di ammoniaca rilasciati dal substrato e, comunque, in grado di non condizionare l’emissione naturale dei gas. I sistemi utilizzati sono (i) eddy covariance, sistema micrometeorologico, composto da un anemometro ad ultrasuoni ed un quantum cascade laser (QC-TILDAS), strumento in grado di leggere la concentrazione di ammoniaca 10 volte al secondo con una sensibilità dell’ordine del ppb e (ii) a diffusione passiva (ALPHA badges), metodologia basata sulla cattura del gas su substrato acido.
I flussi di volatilizzazione sono stati stimati all’interno 3 aziende rappresentative della pianura lombarda, esaminando i rilasci generati dall’utilizzo di 2 tipologie di fertilizzanti, concimi organici (effluenti di allevamento bovino) e concimi minerali (urea), adottando le consuete operazioni di fertilizzazione previste dalle aziende stesse
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