1,720,970 research outputs found
A Biogeochemical analysis of Mediterranean ecosystems and the response to nitrogen deposition: an insight on the carbon and nitrogen cycle in Mediterranean Ecosystems
Get PDFThe carbon (C) and nitrogen (N) cycles have been drastically altered by humans as result of the increasing demand for energy, raw material and food. Combustion of fossil fuels and increasing industrial activities are linked with the emission of carbon dioxide (CO2), which is largely responsible for the rise in atmospheric CO2concentration during the past 50 years. At the same time, there has also been an increase in the concentration of oxidized (NOX) and reduced (NH3) nitrogenous compounds in the atmosphere, largely attributable to vehicular traffic and agricultural practice. In dry and hot conditions of the Mediterranean, the interaction of reactive N with plants and soils didn’t receive much attention. The thesis strongly contributes to fill this knowledge gap with research on the belowground part of the cycles. The work has been part of NitroMed, exciting new network of N deposition experiments in the Mediterranean. More specifically this PhD dissertation bring an insights to the role of N emission in Mediterranean basin through a review of existing literature (ch2), an improved understanding on the role of biocrusts in dryland ecosystem functioning (ch3), an in-depth understanding on how increased N deposition can first stimulate and in the longer term (or at higher deposition rates) break organic matter mineralisation in soils (ch4) and an elegant proposal of mechanistic understanding on N deposition effects on soil biological activity and C mineralization (ch5)
Effects of vine water status and exogenous abscisic acid on berry composition of three red wine grapes grown under mediterranean climate
No full textAn Index for User-Friendly Proximal Detection of Water Requirements to Optimized Irrigation Management in Vineyards
No full textWe propose an index for proximal detection of water requirements to optimize the use of water resources in arid and semi-arid wine growing regions. To test the accuracy and representativeness of the proposed irrigation need index (IIN), plant water status and physiological performances were monitored during seasons 2019 and 2020 in two grapevine varieties with different anisohydric degree (Vermentino and Cannonau) grown in 3 sites in Sardinia (Italy). Daily leaf gas exchange curves and stem water potential were recorded. Canopy temperature was monitored, using both thermistor sensors (Tc) and infrared thermometry (IR). Meteorological data, including dry and wet bulb temperatures were collected to compute and parametrize IIN, based on energy balance equation. Vineyard water balance, thermal time and irrigation water productivity were characterized. Linear regression analysis allowed to validate IIN for both varieties and to establish target thresholds for mild, moderate and severe water deficit to optimize irrigation for high yield and quality objectives. IIN well represents plant water status, using either Tc or IR, and allows rapid and easy detection of water and heat stress condition, even when a stricter stomatal control determines slighter variation and lower response of stem water potential, as in plants with low anisohydric degree
A Biogeochemical analysis of Mediterranean ecosystems and the response to nitrogen deposition: an insight on the carbon and nitrogen cycle in Mediterranean Ecosystems
Get PDFThe carbon (C) and nitrogen (N) cycles have been drastically altered by humans as result of the increasing demand for energy, raw material and food. Combustion of fossil fuels and increasing industrial activities are linked with the emission of carbon dioxide (CO2), which is largely responsible for the rise in atmospheric CO2 concentration during the past 50 years. At the same time, there has also been an increase in the concentration of oxidized (NOX) and reduced (NH3) nitrogenous compounds in the atmosphere, largely attributable to vehicular traffic and agricultural practice. In dry and hot conditions of the Mediterranean, the interaction of reactive N with plants and soils didn’t receive much attention. The thesis strongly contributes to fill this knowledge gap with research on the belowground part of the cycles. The work has been part of NitroMed, exciting new network of N deposition experiments in the Mediterranean. More specifically this PhD dissertation bring an insights to the role of N emission in Mediterranean basin through a review of existing literature (ch2), an improved understanding on the role of biocrusts in dryland ecosystem functioning (ch3), an in-depth understanding on how increased N deposition can first stimulate and in the longer term (or at higher deposition rates) break organic matter mineralisation in soils (ch4) and an elegant proposal of mechanistic understanding on N deposition effects on soil biological activity and C mineralization (ch5)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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