169,951 research outputs found
Tecniche innovative di stima del regime dei deflussi superficiali e di classificazione dei bacini idrografici in assenza di osservazioni idrometriche
No full textCoordinatore nazionale: Pierluigi Claps
Responsabile scientifico: Attilio Castellarin
L’Unità di Ricerca (UR) dell’Università degli Studi di Bologna, con riferimento al contesto geomorfologico e climatico del nostro Paese, condurrà una serie di indagini orientate al miglioramento delle stime indirette (c.d., condotte in assenza di osservazioni) del regime dei deflussi idrici superficiali. Il quadro d’indagine si articola in tre macroattività distinte: (a) confronto tra diverse tecniche di classificazione dei bacini idrografici, proposte in letteratura a supporto dell’analisi regionale di frequenza delle portate di piena e di magra (tecniche tradizionali e tecniche innovative basate sull’uso di reti neurali artificiali; Workpackage, WP: A1) ; (b) messa a punto e sperimentazione di tecniche di regionalizzazione dell’informazione idrometrica di nuova concezione, basate su procedure geostatistiche che prescindono dall’identificazione di raggruppamenti di bacini idrologicamente affini (WP: A1 e A2); (c) regionalizzazione dei parametri di un modello matematico di trasformazione afflussi-deflussi (TOPKAPI, sviluppato dall’UR; WP: B2 e B3). La macroattività (c) si avvarrà dei risultati delle macroattività (a) e (b) per l’identificazione dei descrittori geomorfoclimatici più significativi e della la tecnica di regionalizzazione più efficace.
Le macroattività (a) e (b) verranno sviluppate in stretta collaborazione con le UR attive presso il Politecnico di Torino (PoliTO) ed il Politecnico di Bari (PoliBA). L’ambito d’indagine coinciderà con il sistema nazionale di bacini idrografici (circa 380 bacini strumentati) relativamente al problema della stima indiretta della piena indice (valore atteso del massimo annuale di portata al colmo di piena) e della portata media annuale. Successivamente, le indagini verranno approfondite per un insieme di bacini marchigiano-abruzzesi relativamente alla stima indiretta di alcuni indici di deflusso di piena e di magra. Tutti i modelli regionali di stima indiretta messi a punto verranno cross-validati mediante procedure di ricampionamento dell’informazione idrologica, ottenendo utili indicazioni relativamente all’incertezza delle stime conseguibili per bacini non strumentati. La macroattività (c) verrà sviluppata con riferimento all’insieme di bacini appenninici tosco-emiliani e romagnoli per i quali l’UR ha condotto in passato applicazioni del TOPKAPI (c.d. principali affluenti appenninici del Fiume Po, bacino del Fiume Reno e suoi affluenti romagnoli). Infine, utili indicazioni sulle tematiche del Progetto di Ricerca relativamente al settore alpino occidentale verranno conseguite attraverso un’applicazione del TOPKAPI distribuito al bacino campione del Sangone (collaborazione con la UR del PoliTO).
Risultati attesi e prodotti: (1) proposta di classificazione del sistema nazionale di bacini idrografici (Macroattività a, WP: A1); (2) messa a punto di tecniche innovative per il miglioramento delle stime indirette di portate di piena e di magra (Macroattività b, WP: A1 e A2); (3) regionalizzazione di un modello afflussi-deflussi che ne consenta l’applicazione in bacini non strumentati dell’appennino tosco-emiliano e romagnolo (Macroattività c, WP: B2 e B3)
Preveraison water deficit accelerates berry color change in merlot grapevines
No full textIn red varieties, berry color change from green to red is one of the first events associated with ripening and is often used as an indicator of veraison by viticulturists. Water deficit can accelerate ripening and increase pigment accumulation in the berry skin. The impact of water deficit on the timing and progression of berry color change in the vineyard has been largely overlooked. Here we present three years of observations (2011 to 2013) on the progression of color change in Merlot vines subjected to water deficit (WD) or irrigation (C) regimes. Water deficit did not affect the date at which berries started changing color in 2011 and 2012, but pigmentation began three days earlier in WD than in C vines in 2013. Water deficit accelerated pigmentation in all three years and WD berries completed color change five days earlier than C berries on average. © 2016 by the American Society for Enology and Viticulture
Osservazioni su Platichthys flesus italicus (Gthr.) (Osteichthyes, Pleuronectiformes) del Golfo di Trieste.
No full textFrammento premaculare di telino chirurgico: una possibile causa di deficit visivo post-operatorio
No full textAssessing the historical residual flood-risk evolution over large floodable areas: dependence of the results on the 2D hydrodynamic numerical model
No full textThis study investigates the evolution of the flood risk along the middle-lower reach of the River Po (length ~350 km,
Northern Italy). The analysis starts from the common perception that, due to a combination of different causes, the flood
risk is dramatically increasing in Europe and in other areas of the world, which is supported by the steadily increasing
economic flood losses recorded worldwide. We refer in particular to the residual flood-risk and we consider an inundation
scenario simulated by means of a simplified quasi-two-dimensional (quasi-2D) hydrodynamic model that reproduces the
hydraulic behavior of a large floodable area outside the main embankment system of the Po river (named “C-Buffer”) for
an exceptional flood event with a 500-year return period; then we perform a detailed flood risk assessment for different
land-use scenarios and population dynamics that have been observed for the C-Buffer over the last five decades. The
detailed flood-risk assessment refers separately to four hydraulic compartments located within the C-Buffer, which
according to the study inundation scenario are flooded during the exceptional event. In particular, the analyses use flooddamage
curves proposed in the literature coupled with a reproduction of the inundation dynamics simulated by two fully
two-dimensional (2D) hydrodynamic models based on 2D shallow water Saint-Venant equations: Hec-Ras 5.0 and
Telemac-2D. The former model has been recently released and enables users to perform combined one-dimensional (1D)
and 2D unsteady-flow simulations (i.e. combining 1D reaches and storage areas with 2D flow areas schematized with
finite-volume method), while the latter is a widely employed and well known 2D finite-element scheme. The comparison
enabled us to assess how recent land-use changes affected the residual risk in the study area and, indirectly, to quantify
the dependence of flood-risk assessments on the considered 2D model, i.e. Telemac-2D and the new Hec-Ras 5.0
Multivariate probabilistic regional envelopes of extreme floods
No full textRecently probabilistic regional envelope curves of extreme floods (RECs) were introduced along with an estimator of the exceedance probability of a REC that accounts for the impact of correlation among flood sequences. The dependence of traditional envelope curves on drainage area alone impacts their reliability for estimating the design-flood. We introduce multivariate regional envelopes (MVEs) of extreme floods which are envelope surfaces (or hyper-surfaces) that represent the bound on our flood experience in a region in terms of geomorphologic and climatic basin descriptors. An empirical MVE is derived for a group of 34 unregulated catchments located in northern-central Italy. A cross-validation procedure that simulates ungaged conditions at every site in the region is used to compare the reliability of design flood estimates resulting from REC, MVE and an index-flood approach. We document that MVEs outperform RECs
and provide flood quantile estimates at ungaged sites that are nearly as reliable as index
flood quantiles
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
Probabilistic Envelope Curves for Extreme Rainfall Events - Curve Inviluppo Probabilistiche per Precipitazioni Estreme
No full textA regional envelope curve (REC) of flood flows summarises the current bound on our experience of extreme floods in a region. RECs are available for most regions of the world. Recent scientific papers introduced a probabilistic interpretation of these curves and formulated an empirical estimator of the recurrence interval T associated with a REC, which, in principle, enables us to use RECs for design purposes in ungauged basins.
The main aim of this work is twofold. First, it extends the REC concept to extreme rainstorm events by introducing the Depth-Duration Envelope Curves (DDEC), which are defined as the regional upper bound on all the record rainfall depths at present for various rainfall duration. Second, it adapts the probabilistic interpretation proposed for RECs to DDECs and it assesses the suitability of these curves for estimating the T-year rainfall event associated with a given duration and large T values. Probabilistic DDECs are complementary to regional frequency analysis of rainstorms and their utilization in combination with a suitable rainfall-runoff model can provide useful indications on the magnitude of extreme floods for gauged and ungauged basins.
The study focuses on two different national datasets, the peak over threshold (POT) series of rainfall depths with duration 30 min., 1, 3, 9 and 24 hrs. obtained for 700 Austrian raingauges and the Annual Maximum Series (AMS) of rainfall depths with duration spanning from 5 min. to 24 hrs. collected at 220 raingauges located in northern-central Italy. The estimation of the recurrence interval of DDEC requires the quantification of the equivalent number of independent data which, in turn, is a function of the cross-correlation among sequences. While the quantification and modelling of intersite dependence is a straightforward task for AMS series, it may be cumbersome for POT series. This paper proposes a possible approach to address this problem
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
Una interpretazione probabilistica della curva inviluppo delle portate al colmo di piena
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