305,150 research outputs found
Self-made microlysimeters to measure soil evaporation : a test on aerobic rice in northern Italy
No full textSoil water balance researches aimed at improving crop water use efficiency often require the determination of soil evaporation. In this technical note, the performance of simple and cheap self-made microlysimeters for the measurement of soil evaporation was tested in an aerobic rice field managed by intermittent irrigation. Six microlysimeters obtained by cutting commercial PVC pipes and closing the bottom ends with caps were positioned in appropriate PVC outer casings installed into the soil. Three measurement campaigns (for a total of 11 measurement periods) were carried out in different vegetation cover conditions (rice development, rice maturity and after the crop harvest). Evaporation amounts were analysed with respect to climatic data, vegetation cover and soil water status and, finally, compared with the simulated results of a FAO Penman–Monteith “dual crop coefficient” model implemented with site-specific data. Evaporation rates in the three campaigns were closely dependent on the evaporative demand of the atmosphere ETo (R2 = 0.96, 0.98, 0.96), while the slope of the linear regression curve was strongly related to the vegetation cover (b = 0.29, 0.12, 0.94); soil water content, always rather high during the experiments, did not affect the evaporation rate. Measured and simulated evaporation amounts showed a close agreement: the linear regression was characterized by slope and R2 of 0.98 and 0.95, while RMSE and NSE indices were 0.15 and 0.94. From the tests conducted, we can conclude that the self-made microlysimeters presented in this note are affordable instruments for measuring soil evaporation, at least in temperate climate conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Gestione alternativa dell’acqua in risaia e implicazioni agro‐ambientali
No full textLe tecniche alternative di gestione dell’acqua in risaia influenzano fortemente le condizioni redox dei suoli, con importanti implicazioni sulla disponibilità di nutrenti, sull’emissione di gas ad effetto serra (GHG), sulla qualità dell’acqua, sul bilancio idrico, così come sulla produttività della risaia. Tutti questi aspetti sono stati indagati in una sperimentazione che ha comparato tre tecniche alternative di gestione dell’acqua nel corso di due stagioni colturali (2012‐2013): (i) semina in acqua e sommersione continua (FLD); (ii) semina interrata e sommersione posticipata (DRY); (iii) semina interrata e irrigazioni turnate (IRR).Elevate produzioni di granella sono state ottenute nei trattamenti FLD e DRY, mentre IRR ha mostrato produzioni inferiori. Le analisi della soluzione del suolo hanno evidenziato un incremento nella concentrazione di ammonio in corrispondenza delle fertilizzazioni azotate nelle fasi di pre‐semina e accestimento, in particolar modo nei trattamenti DRY e IRR. Inoltre, mentre la limitata nitrificazione in FLD ha comportato basse concentrazioni di nitrati, DRY e IRR hanno mostrato invece importanti concentrazioni e fenomeni di lisciviazione lungo tutto il profilo del suolo. Le differenze nelle condizioni redox del suolo hanno influenzato, inoltre, l’emissione di GHG, nell’ordine IRR<<DRY<FLD per il metano e FLD<DRY<<IRR per il protossido d’azoto.Da questi dati si evince che, mentre la semina interrata e sommersione posticipata non risultano aver influenzato significativamente le produzioni, le irrigazioni turnate hanno mostrato una riduzione del 20% del dato produttivo, accompagnata da una difficile gestione dell’N. Entrambe le tecniche con semina interrata possono però offrire una potenziale riduzione dei GHG e dei consumi idrici nei sistemi risicoli
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Gestione alternativa dell'acqua in risaia ed implicazioni agro-ambientali
No full textOBIETTIVO: Valutare come tecniche differenti di gestione dell’acqua possano influenzare aspetti agronomici e ambientali di risaie temperate italiane e le loro implicazioni in termini di performance produttive, di disponibilità e perdita di nutrienti nei suoli e di emissione di gas serra (GHG)
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
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