169,754 research outputs found
Lo studio della vegetazione come base per la programmazione in aree marginali delle Comunità Montane "Catria-Nerone" e "Alto Chiascio".
No full textProgetto finalizzato IPRA "Aree marginali
Cosa è necessario intendere per servizio ecosistemico. Il contributo della fitosociologia all’interno delle innovazioni della PAC 2014-2020
No full text
Diachronic analysis of variations induced on the flora and vegetation of river ecosystems by actions taken to reduce the risk of flooding. Case study of the River Chienti (central Adriatic, Italy)
No full textWe present here a diachronic comparison of the ora and vegetation of a stretch of River Chienti, in central Marche (Italy). We assess the impact of mechanical cleaning of the river on its ecological structure and biodiversity. The rst survey was carried out in 1993, and then repeated in the same areas and with the same methodology in 2005, following heavy and repeated hydraulic maintenance of River Chienti. This process included excavation of gravel from the river bed and its accumulation on the river banks, with the objective to broaden and deepen the ow channel. In some places that were under strong anthropic in uence and subjected to continuous erosion, this process was accompanied by work on the protection of the river banks using various materials, to reduce the risk of ooding. In connection with this, it should be noted that the mouth of River Chienti has been de ned as an area at very high hydro-geological risk according to the Speci c Basin Plan (Piano Stralcio di Bacino) for the Hydrogeological Assets of the Basins of Regional Importance (PAI), as approved by Resolution N° 116 of the Regional Council, of 21 January, 2004. This work has resulted in the disappearance of lateral branches of the river that had still or slow- owing water, and mechanical removal of the vegetation of the river bed, and in some instances, also of the river banks. These actions have removed the wet ats at the sides of the main channel, which represen- ted favourable habitats for the establishment of different types of helophytic and hydrophytic plant communities according to the main ecological gradients. These actions that were designed to secure the river banks have led to an upheaval in the vegetation of the alluvial terraces closest to the water course, with profound alterations to the structure of the communities that had developed in the area, resulting in some cases in their disappe- arance. The oristic comparison shows the loss of 95 (69.34%) entities in 2005 in comparison to those surveyed in 1993. The oristic entities that have been lost in the area are mainly those related to helophytic and marsh environments, such as Zannichellia palustris, Nasturtium of cinale and Glyceria notata. On the other hand, particularly invasive exotic entities have appeared, such as Robinia pseudoacacia, Amorpha fruticosa, Arundo donax, Cuscuta scandens subsp cesatiana, Paspalum distichum and Helianthus tuberosus, along with species from the elds or from the surrounding marshy areas, such as Helianthus annuus, Brassica nigra, Rumex crispus and Tripleurospermum inodorum. Analysis of the vegetation has shown a decrease in the plant communities both of the river bed and the river banks, which have been reduced from 15 (in 1993) down to 10 (in 2005). The following associations have disappeared: Zanichellietum palustris, Nasturtietum of cinalis, Helosciadetum nodi ori, Bolboschoenetum maritimi, Glycerietum plicatae, Typhaetum latifoliae, Sparganietum erecti, Saponario-Artemisietum verlotorum, Ranunculetum repentis, Aro italici-Alnetum glutinosae and Salicetum incano-purpureae. The vegetational types that have disappeared can be attributed to the classes Potametea pectinati, Phragmito australis-Magnocaricetea elatae, Agrostietea stoloniferae, Alnetea glutinosae and Salicetea purpureae. The class that has suffered the greatest number of losses is Phragmito australis-Magnocaricetea elatae. Many of the communities that are no longer found have high ecological value, such as Zanichellietum palustris, Nasturtietum of cinalis, Helosciadetum nodi ori, Bolboschoenetum maritimi and Glycerietum plicate
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
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Criteri per la valutazione di biodiversità e stabilità in boschi a governo ceduo
No full textUno studio multidisciplinare, esteso su oltre 85 ha tradizionalmente gestiti a ceduo e qualificati da Scutellario columnae-Ostrietum carpinifoliae, ha permesso di osservare i parametri caratteriz- zanti le diverse fasi di sviluppo della cenosi, la cui compresenza caratterizza le aree forestali ge- stite secondo questa forma di governo. La successione evolutiva della formazione dal momento del taglio fino al primo decennio successivo al suo abbandono gestionale è stata poi ricostruita mediante approccio sincronico. I risultati ottenuti hanno permesso di evidenziare come l’elevato grado di biodiversità e complessità ecologica presente a livello di compresa sia legato non soltan- to alla compresenza di particelle con condizioni dinamico-strutturali differenti, ma anche e so- prattutto al processo di selezione e mantenimento di specie a livello particellare dovuto ai distur- bi legati alla forma gestionale. Modifiche al turno tradizionale implicano effetti non soltanto a livello floristico e strutturale, ma anche a livello di pedofauna, seed bank, necromasse e andamen- to fenologico. Questo comporta alterazioni degli effetti feedback e una sostanziale modifica del si- stema, che perde la sua caratteristica resilienza a favore di una piú spiccata resistenza. Al ri- crearsi delle condizioni di scopertura, la cenosi presenta evidenti alterazioni, tra cui la scompar- sa di un cospicuo numero di specie animali e vegetali. Appare quindi ovvio come la valutazione del valore in termini di biodiversità e complessità ecologica non possa essere effettuata prenden- do in esame i soli momenti finali del turno, senza tener presente il contingente floristico caratte- rizzante i primi anni successivi al taglio, composizione e vitalità della seed bank, strutturazione delle forme di humus ed autoecologia delle keystone species
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
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