1,720,997 research outputs found
Evaluating short-term tidal flat evolution through UAV surveys: A case study in the Po Delta (Italy)
No full textThe use of Unmanned Aerial Vehicles (UAV) on wetlands is becoming a common survey technique that is extremely useful for understanding tidal flats and salt marshes. However, its implementation is not straightforward because of the complexity of the environment and fieldwork conditions. This paper presents the morphological evolution of the Po della Pila tidal flat in the municipality of Porto Tolle (Italy) and discusses the reliability of UAV-derived Digital Surface Models (DSMs) for such environments. Four UAV surveys were performed between October 2018 and February 2020 on an 8 ha young tidal flat that was generated, amongst others, as a consequence of the massive sediment injection into the Po Delta system due to the floods of the 1950s and 1960s. The DSM accuracy was tested by processing (i.e., photogrammetry) diverse sets of pictures taken at different altitudes during the same survey day. The DSMs and the orthophotos show that the tidal flat is characterised by several crevasse splays and that the sediment provision depends strictly on the river. During the study period, the sediment budget was positive (gaining 800 m3/year and an average rate of vertical changes of 1.3 cm/year). Comparisons of DSMs demonstrated that neither lower flight altitudes (i.e., 20–100 m) nor the combination of more photos from different flights during the same surveys necessarily reduce the error in such environments. However, centimetric errors (i.e., RMSEs) are achievable flying at 80–100 m, as the increase of GCP (Ground Control Point) density is the most effective solution for enhancing the resolution. Guidelines are suggested for implementing high-quality UAV surveys in wetlands
Security, immigration and development assistance: an integrated approach
No full textThe European Union’s security and immigration policy requires a set of actions coordinated between the Union and individual Member States, plus a consistent policy of development cooperation within the frame work of European Neightbourhood Policy (ENP). This article takes a look at the European approach in these policy areas. After considering the economic and social causes of international migration, it dwells on the prospective “migratory pressure” on Europe, which is expected to be strong, especially from the southern shores of the Mediterranean. The authors stress the essential role of European Neightbourhood Policy, which must promote development and democracy in the countries bordering on the Union. It is necessary to create an area of stability and security within which to achieve negotiated regulation of migratory flows. It is argued that the financial resources for ENP are inadequate and that a decisive role will be played by bilateral aid to the bordering countries from EU member States. Nevertheless, the author observe that these resources are subject to the budgetary constraints of the Stability and Growth Pact and accordingly recommend that the development assistance should also be treated as investment in stability and security, the benefits of which will be reflected in diminished future costs for individual European countries. The authors therefore call for the application of the “golden rule” to this expenditure, treating it on a par with investment and R&D spending for purpose of calculating government deficits
La Valsat del Piano di Gestione della Qualità dell’Aria della Provincia di Bologna
No full textLa Valsat del Piano di gestione della qualità dell’aria descritta contributo si è avviata a partire dalla definizione e condivisione degli obiettivi di piano e dalla loro declinazione in azioni all’interno del documento preliminare (valutazione preliminare) e si è integrata nel corso della redazione del piano, orientandone le scelte secondo i criteri, ormai universalmente condivisi, della sostenibilità (Valsat ex-ante). Essa costituirà inoltre parte integrante del piano adottato, fornendo all’amministrazione gli strumenti per il monitoraggio degli effetti derivanti dall’attuazione delle azioni in esso contenute (Valsat in itinere) e per valutare l’efficacia e l’efficienza degli interventi che sono stati realizzati (Valsat ex-post). La metodologia seguita deriva dalle esperienze condotte ed in corso in provincia; essa si sviluppa in coerenza con quanto previsto dalla L.R. 20/2000 e dalla Dir. 42/2001/CE e accoglie le indicazioni delle linee guida predisposte nel corso degli ultimi anni a livello nazionale ed internazionale (con riferimento specifico alle linee guida del Progetto Enplan, 2004), collocandosi all’interno del quadro di riferimento costituito dalla Valsat del PTCP (Provincia di Bologna, 2003). Essa si articola in diverse fasi: analisi dello stato di fatto, valutazione di coerenza, valutazione delle alternative; inoltre, viene descritto il processo partecipativo attivato e sono indicate le modalità attraverso cui verrà predisposto il monitoraggio degli effetti dell’attuazione del piano. Infine, vengono formulate alcune osservazioni critiche allo scopo di evidenziare i punti di forza e di debolezza della valutazione descritta
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
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