1,720,964 research outputs found
Redating the arrival of Tropaeolum minus in Italy
Full text linkAt a European level, Tropaeolum minus is the first species of this genus that arrived in our continent, around 1570, immediately used as an ornamental, vegetable and pharmaceutical plant. According to Italian sources, instead, T. minus arrived in Italy only in 1642: the species of this genus which was known in Italy at the time was T. majus, imported in 1596. However, in the Italian Renaissance herbaria, there are four specimens dated to the last decades of 1500, clearly recognisable as T. minus, which would confirm its import around 1570. Thanks to the analysis of these herbarium specimens and documental sources of the second half of the XVI century (Ulisse Aldrovandi's manuscripts and watercolour plates, the lists of species cultivated in that period in the principal Italian botanical gardens, the manuscript code I cinque libri di piante by Pietro Antonio Michiel), it is possible to demonstrate that the arrival of T. minus in Italy has to be redated at the second half of the XVI century. Furthermore, this work allowed the specimens of Tropaeolum preserved in the Erbario Aldrovandi to be identified correctly, which were formerly attributed to T. majus following the Italian scientific literature available so far
CONSERVAZIONE INTEGRATA DI UNA PIANTA RARA E MINACCIATA E DELLA COMUNITA' DEI SUOI IMPOLLINATORI SELVATICI: PROGETTO LIFE+ PP-ICON (LIFE09/NAT/IT/000212)
No full textIl progetto PP-ICON (Plant Pollinator Integrated CONservation approach: a demonstrative
proposal) è un progetto LIFE+ Biodiversità della durata di 4 anni incentrato sulla conservazione
integrata di una pianta localmente rara, Dictamnus albus L., e sulla comunità dei suoi impollinatori.
Il sito di intervento si trova all'interno di un’area protetta della provincia di Bologna (Parco
Regionale dei Gessi Bolognesi e Calanchi dell'Abbadessa), che è anche un sito di interesse
comunitario (SIC-ZPS IT4050001 Rete Natura2000).
Le azioni si concentrano in quattro ambiti principali: gestione dell'habitat, salvaguardia degli
impollinatori, sensibilizzazione degli stakeholders e divulgazione. Gli interventi sull’habitat sono
consistiti nella creazione di schiarite boschive, al fine di ristabilire le migliori condizioni ambientali
per la persistenza della pianta, che soffre per la chiusura del bosco. Sono stati individuati gli
impollinatori effettivi del dittamo, al fine di fornire loro siti di nidificazione idonei, e alcune specie
di bombi sono state allevate artificialmente e reintrodotte nella zona. Il sostentamento degli
impollinatori è stato anche favorito dall'incremento delle fonti mellifere, ossia della flora spontanea
necessaria a fornire loro nettare e polline. A tale scopo sono state scelte 16 specie già presenti
nell'area e con una fioritura scalare, per garantire la presenza di fonti alimentari per tutto il periodo
di sviluppo degli insetti. Il successo delle azioni di conservazione viene valutato attraverso il
monitoraggio periodico della fitness della pianta e della diversità degli impollinatori.
Dopo tre anni dall'inizio del progetto la gestione del bosco ha dato esito positivo, con un incremento
della luce incidente nelle due aree di taglio di rispettivamente 5 e 2 volte rispetto alle due aree di
controllo, e un aumento di 6 volte del numero di piante fiorite. L'introduzione di 6 gruppi di nidi
artificiali ha avuto successo per diverse specie di api solitarie (es. varie Megachilidae e Xylocopa
sp.), mentre i 10 nidi per bombi non sono stati colonizzati. Tuttavia, in tre anni, 17 colonie di
Bombus terrestris sono state allevate con successo in laboratorio e reintrodotte nella zona. Le piante
nettarifere trapiantate vengono assiduamente visitate dagli impollinatori selvatici e, anche se i dati
del monitoraggio indicano ancora una generale scarsità di fauna impollinatrice, vi è una relazione
positiva tra abbondanza degli impollinatori e diversità delle specie di fiori; nell’anno successivo
all’introduzione delle nettarifere infatti l’indice di Shannon è aumentato in media di 0,25 punti ogni
mese rispetto all’anno precedente.
Gli eventi di divulgazione, che si concentrano sul rapporto tra piante e impollinatori e sulle strategie
per la loro conservazione, hanno attirato un numero sempre crescente di persone negli anni del
progetto, contribuendo a sensibilizzare l'opinione pubblica sull'importante tema della conservazione
della biodiversità
Botanical memory: five centuries of floristic changes revealed by a Renaissance herbarium (Ulisse Aldrovandi, 1551–1586)
Full text linkWe analysed the spatially explicit floristic information available in the herbarium of Ulisse Aldrovandi (1551–1586) to track floristic changes in the surroundings of Bologna across five centuries. Aldrovandi's data were compared with the Flora della Provincia di Bologna by Girolamo Cocconi (1883) and the Floristic Database of Emilia-Romagna (1965–2021). We explored potential variations in native range and life forms composition, and habitat affinity of the species in the three floras, also contrasting between native and alien species. Native species, mainly in terms of variations of hydro-hygrophytes, chamaephytes and therophytes, provide clear signals of human disturbance and habitat loss. Signals of climate change are provided by the high-mountain species, that were comparably rare between Aldrovandi and current flora and more represented in Cocconi, probably reflecting the effect of the Little Ice Age. Our findings also indicate the increasing importance of alien species from the Renaissance onwards. In this perspective, Aldrovandi's herbarium preserves the memory of the first signs of a radical transformation of the European flora and habitats. Finally, the study warns about the risk of dismissing herbaria and herbarium specimens collection, which would cause irreparable lacunas in our botanical memory, hindering our ability to predict biodiversity trajectories
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
Orto botanico ed erbario dell'università di Bologna = Botanic garden and herbarium of the university of Bologna
No full textAppropriate 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
- …
