1,721,004 research outputs found
Onopordon acanthium subsp. acanthium in una discarica della Pianura Padana (Piacenza)
No full textOnopordum acanthium subsp. acanthium in a closed landfill of Po Valley (Piacenza) -
This work aims to report a station, located in a closed landfill of Piacenza (Po Valley, Italy), where the vegetation is characterized
by the dominance of Onopordum acanthium L. subsp. acanthium. The results returned by floristic, ecological and
phytosociological analysis, showed peculiar aspects that express how the plant community is adapted to the environmental
conditions of the area
Hydrological properties of natural and reconstituted soils: compared methods
No full textAmong the physical parameters of soil, the hydrological properties fulfil an important role in illustrating its quality. The trend of the water retention curve indicates the condition of the soil and allows us to define, together with chemical parameters, its eventual state of decline. This work aims to describe the hydrological properties of different types of soils using various techniques and to compare the results. The soils examined can be subdivided into two types: natural soils and reconstituted soils obtained by a chemical mechanical treatment (patented by m.c.m. Ecosistemi s.r.l.) where an initial disgregation is followed by a reconstitution incorporating soil improvers,by a further polycondensation with humic acids and a final restoration. This study is part of a LIFE+ project, co-financed by the European Union and is entitled "Environmental recovery of degraded soils and desertified by a new treatment technology for land reconstruction" (Life 10 ENV IT 400 "New Life"). It aims to test the effectiveness of the reconstitution treatment of the soils in combatting their decline. Natural soils, on which this work is concentrated, are extreme soils: sandy soil (86.2% sand), silt loam soil (42.5% sand, 49.9% silt), clayey soil (54.6% clay, 38.5% silt); reconstituted soils were produced from these. Samples were taken to carry out analyses on water retention through the use of Richards pressure plates. Other samples were used to determine the saturation point and to carry out trials in pots in order to determine the moisture at the permanent wilting point. The information obtained from these laboratory tests were compared to the results of soil pedofunctions
Environmental quality of a semi-natural area of the Po Plain (northern Italy): aspects of soil and vegetation.
No full textThis work, originating in the preliminary analyses of a Life project and co-financed by the European Union ("Environmental recovery of degraded soils and desertified by a new treatment technology for land reconstruction", Life 10 ENV IT 400 "New Life"; http://www.lifeplusecosistemi.eu), aims to evaluate the environmental quality of a semi-natural area of the Po Valley (northern Italy) by analysing the characteristics of soil and vegetation. The area of study is located in the municipal territory of Piacenza (Emilia-Romagna, Italy) along the eastern shores of the river Trebbia and is made up of the closed landfill of Solid Urban Waste of Borgotrebbia (active from 1972 to 1985) and of the neighbouring areas (in North-South order: riverside area, northern borders of the landfill, landfill disposal, southern borders and cultivated corn fields). For each area pedological and vegetational analyses were carried out and in particular, as regards the soil, various chemical-physical analyses were done among which: pH, organic carbon, total nitrogen, salinity, exchangeable bases and granulometry. The ground vegetation data were collected using phytosociological relevés according to the method of the Zurich-Montpellier Sigmatist School, (Braun-Blanquet, 1964). For the analysis of the environmental quality of each area, the floristic-vegetation indexes system was applied as proposed by Taffetani & Rismondo (2009) (updated by Rismondo et al., 2011) conveniently created for analysing the ecological functionality of the agro-ecosystems. The results obtained by such applications drew attention to a dynamic vegetation mass in the landfill which, despite a value of the floristic biodiversity index (IFB) comparable to that of the borders, shows a much lower value of the maturity index (IM). This is due to the elevated percentage of annual species (index of the therophytic component = 52.78%) belonging to the phytosociological class Stellarietea mediae Tüxen, Lohmeyer & Preising ex von Rochow 1951. From a first comparison of the information obtained from the vegetation and soil analyses, it would appear that the areas with a lower environmental quality are those in which there is (or was) a greater human disturbance
I caratteri del suolo di un'area degradata: parametri chimici e indicatori ecologici a confronto
Full text linkI risultati dello studio ecologico della vegetazione presente in un'area degradata sono stati confrontati con quelli ottenuti dalle analisi pedologiche al fine di apprendere quelle che sono le caratteristiche del suolo e valutare le informazioni restituite dall'applicazione congiunta dei due approcc
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
Fluttuazioni stagionali della vegetazione di una discarica dismessa del piacentino
No full textIl presente lavoro si inserisce in un progetto life co-finanziato dall’Unione Europea (Life+, LIFE 10 ENV/IT/0400 NewLife; http://www.lifeplusecosistemi.eu) volto alla riqualificazione ambientale di una ex-di- scarica per mezzo di una tecnologia innovativa, ideata dalla società m.c.m. Ecosistemi titolare dell’iniziativa. L'area di studio è ubicata nel territorio comunale di Piacenza (Emilia-Romagna) presso la località Borgotrebbia e presenta una copertura vegetazionale costituita in prevalenza da specie erbacee nitrofile di ambienti degradati (Giupponi et al., 2013a; Giupponi et al., 2013b). Giupponi et al. (2013c) hanno individuato cinque tipologie ve- getazionali che rappresentano due varianti e tre facies di una medesima comunità (Convolvolus arvensis-Cynodon dactylon) appartenente alla classe Stellarietea mediae: facies a Rumex crispus, facies ad Elymus repens (con specie tolleranti ai metalli pesanti nel suolo), facies a Hordeum murinum (indicatrice di suoli secchi), variante a Xanthium orientale subsp. italicum (ricca di terofite eliofile e termofile), variante a Alopecurus rendlei (variante più evoluta di suoli umidi).
L’obiettivo di questo studio è evidenziare e descrivere le fluttuazioni stagionali (floristiche e fisionomiche) delle diverse tipologie vegetazionali presenti nell'ex-discarica al fine di ampliare le conoscenze riguardanti le comunità che si instaurano in luoghi particolarmente degradati dall'attività antropica.
Sono stati realizzati 35 rilievi fitosociologici, uno per ciascuna cenosi individuata da Giupponi et al. (2013c), condotti a scadenza mensile da aprile a ottobre 2013. Per ciascuna delle cinque tipologie vegetazionali è stata effettuata la cluster analysis dei rilievi per individuare le similitudini floristico-fisionomiche della vegetazione e identificarne così gli aspetti stagionali. Si è poi proceduto ad analizzare i vari caratteri stagionali delle cinque tipologie vegetazionali dal punto di vista floristico, ciò elaborando e confrontando i rispettivi spettri biologici.
In tutti i dendrogrammi ottenuti sono stati individuati due raggruppamenti principali che definiscono un aspetto primaverile e uno estivo-autunnale di ciascuna comunità vegetale. Gli aspetti primaverili si differenzino da quelli estivo-atunnale per la presenza di Bromus sterilis, Bromus hordeaceus, Geranium dissectum, Alopecurus rendlei e Stellaria media. Amaranthus retroflexus, Atriplex patula, Cynodon dactylon e Polygonum aviculare sono pre- senti in tutte e cinque le facies estivo-autunnali. L’unica specie che compare da aprile a ottobre in tutti i rilievi è Elymus repens che presenta buoni valori di copertura nei mesi di maggio, giugno e luglio. Considerando gli spettri biologici ponderati dei singoli aspetti primaverili si è notata una preponderanza di terofite, rispetto a geofite ed emicriptofite. Negli aspetti estivo-autunnali si è osservato un generale aumento delle specie con adat- tamenti ad ambienti aridi. Si è notato infatti un aumento delle terofite, ma anche di quelle geofite quali Cynodon dactylon e Convolvulus arvensis i cui indici di Landolt esprimono adattamenti ai suoli secchi. Nei mesi estivi infatti si manifestano condizioni sfavorevoli causate in prevalenza da aridità edafica, ciò è imputabile anche alle pessime caratteristiche idrogeologiche del suolo di copertura
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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