283 research outputs found
Evidence and Implications of Hydrological and Climatic Change in the Reno and Lamone River Basins and Related Coastal Areas (Emilia-Romagna, Northern Italy) over the Last Century
Climate change and human activities have consequences on coastal areas as they affect hydrological processes in the related river basins. The riverine sediment supply to the beaches of the Emilia-Romagna coast, a highly urbanized area with high economic and naturalistic value, has been heavily impacted by human activities throughout the catchment, reducing solid transport to the coast and increasing the threat of coastal erosion and flooding. Despite the introduction of safeguard policies in the early 1980s and the consequent stoppage of such activities, the expected return in solid transport has not yet been reflected at the coast. To better understand the various processes acting at the river basin scale, we utilized empirical mode decomposition to analyze the variability in different parameters (river discharge, rainfall, air temperature, and sea level) from the headwaters to the coast of the Reno and Lamone rivers over the last century. The anthropogenic footprint, linked to the large-scale dimming/brightening phenomenon, is visible in the long-term trends. Moreover, natural signals with variable periodicity are evident and partially correlated with two major climate modes (North Atlantic Oscillation and Atlantic Multidecadal Oscillation). The coupled interactions among these processes, combined with the changes in land use and evapotranspiration during the last century, have resulted in the prolonged scarcity of river sediment supply and a long-term trend of erosion of the coastal area
Sea-Level Change along the Emilia-Romagna Coast from Tide Gauge and Satellite Altimetry
Coastal flooding and retreat are markedly enhanced by sea-level rise. Thus, it is crucial to determine the sea-level variation at the local scale in order to support coastal hazard assessment and related management policies. In this work we focus on sea-level change along the Emilia-Romagna coast, a highly urbanized, 130 km-long belt facing the Northern Adriatic Sea, by analysing data from three tide gauges (with data records in the last 25-10 years) and related closest grid points from ESA_CCI monthly gridded satellite altimetry. The results reveal that the rate of sea-level rise observed by altimetry is coherent along the coast (2.8 \ub1 0.5 mm/yr) for the period 1993-2019 and that a negative acceleration of -0.3 \ub1 0.1 mm/yr is present, in contrast with the global scale. Rates resulting from tide gauge time series analysis diverge from these values mainly in consequence of a large and heterogeneous rate of subsidence in the region. Over the common time span, altimetry and tide gauge data show very high correlation, although their comparison suffers from the short overlapping period between the two data sets. Nevertheless, their combined use allows to assess the recent (last 25 years) sea-level change along the Emilia-Romagna coast and to discuss the role of different interacting processes in the determination of the local sea level
Submarine depositional terraces at Salina Island (Southern Tyrrhenian Sea) and implications on the Late-Quaternary evolution of the insular shelf
The integrated analysis of high-resolution multibeam bathymetry and single-channel seismic profiles around Salina Island allowed us to characterize the stratigraphic architecture of the insular shelf. The shelf is formed by a gently-sloping erosive surface carved on the volcanic bedrock, mostly covered by sediments organized in a suite of terraced bodies, i.e. submarine depositional terraces. Based on their position on the shelf, depth range of their edge and inner geometry, different orders of terraces can be distinguished. The shallowest terrace (near-shore terrace) is a sedimentary prograding wedge, whose formation can be associated to the downward transport of sediments from the surf zone and shoreface during stormy conditions. According to the range depth of the terrace edge (i.e., 10–25 m, compatible with the estimated present-day, local storm-wave base level in the central and western Mediterranean), the formation of this wedge can be attributed to the present-day highstand. By assuming a similar genesis for the deeper terraces, mid-shelf terraces having the edge at depths of 40–50 m and 70–80 m can be attributed to the late and early stages of the Post-LGM transgression, respectively. Finally, the deepest terrace (shelf-edge terrace) has the edge at depths of 130–160 m, being thus referable to the lowstand occurred at ca. 20 ka. Based on the variability of edge depth in the different sectors, we also show how lowstand terraces can be used to provide insights on the recent vertical movements that affected Salina edifice in the last 20 ka, highlighting more generally their possible use for neo-tectonic studies elsewhere. Moreover, being these terraces associated to different paleo-sea levels, they can be used to constrain the relative age of the different erosive stages affecting shallow-water sectors
Universidad Nacional de Rosario Facultad de Ciencias Exactas, IngenierÃa y Agrimensura Tesis de MaestrÃa Las representaciones -concepciones y conceptos- de los maestros en sus prácticas de aula: un estudio sobre la propagación de la luz y su interacción con los materiales
En esta tesis se han estudiado las representaciones -concepciones y conceptos- de los maestros referidas a la propagación de la luz y su interacción con los materiales y analizar su estructura, indagando su coherencia. Se ha analizado la manera en que, a través del lenguaje verbal escrito y gráfico, se da forma a estas ideas o se interpretan los libros que se utilizan. El estudio, cualitativo-interpretativo, permitió caracterizar la enseñanza de los fenómenos luminosos en el Primer Ciclo de una Escuela Primaria de Santa Fe. El diseño
contempló dos fases, la primera se centró en el estudio de la manera en que los libros existentes en la escuela abordan este contenido. Esto se consideró por dos razones: porque las docentes los emplean para planificar sus clases y, porque se necesitaban esos resultados para elaborar los cuestionarios utilizados en la
segunda fase, para recabar información acerca de las representaciones de las maestras. Esto permitió profundizar acerca de su influencia en la organización e implementación de sus propuestas didácticas. También se discutieron acuerdos y objeciones de las maestras al tratamiento en los libros y las vinculaciones con los materiales curriculares. Finalmente se consideraron implicancias para el contexto educativo derivadas del estudio
Traditional vs. novel approaches to coastal risk management: A review and insights from Italy
Coastal areas frequently face critical conditions due to the lack of adequate forms of land use planning, environmental management and inappropriate coastal risk management, sometimes leading to unexpected and undesired environmental effects. Risk management also involves cultural aspects, including perception. However, the acknowledgement of risk perception by stakeholders and local communities, as one of the social pillars of risk analysis, is often lacking.. Starting from an overview of the risk concept and the related approaches to be addressed, the paper investigates the evolution of coastal risk management with a focus on the Italian case study. Despite the design and adoption of national policies to deal with coastal risks, coastal management still shows in Italy a fragmented and poorly coordinated approach, together with a general lack of attention to stakeholder involvement. Recent efforts in the design of plans aiming at reducing risks derived from climate change and mitigating their impacts (National Strategy on Climate Change Adaptation; National Climate Change Adaptation Plan; National Recovery and Resilience Plan activities) should be effective in updating knowledge about climate change risks and in supporting national adaptation policies
New evidence of the Green Tuff deposits and post-caldera, recent explosive volcanic activity at Pantelleria volcano (Sicily Channel, Italy) recorded in near-vent marine areas
The record of the explosive activity of Pantelleria volcano is well documented by several distal tephra collected in various areas in and around the Mediterranean, while few tephrochronological studies exist on proximal marine areas. In this paper, we investigate three selected coring sites from the northern shoulder of the Pantelleria graben, about 15–30 km from the island, in near-vent position with respect to that volcanic source. Our multiproxy analyses revealed nine tephra layers, totally composed of juvenile materials, mostly ash and pumice fragments, as well as a coarse-grained tephra deposit at the bottom of one of the cores. The major element composition of glass shards indicates a very homogeneous geochemical composition for the tephra layers, suggesting their primary origin. Using litho-stratigraphic and paleoenvironmental proxies, we associated the tephra layers to the latest (<∼13.7 ka) explosive activity of Pantelleria. The coarse-grained deposit, instead, due to its distinctive composition is considered to represent the near-vent, marine equivalent of the distal Y-6 tephra layer, related to the ∼45 ka old co-ignimbrite fallout deposit of the Green Tuff event. The geochemical characterization of such deposit, mostly rhyolitic and partly trachytic, appears to enlarge the bimodal composition recorded in other distal tephra (Y-6) reported in the literature, highlighting the potential of near-vent record in providing additional information on the eruptive history
Coastal Erosion and Flooding Threaten Low-Lying Coastal Tracts at Lipari (Aeolian Islands, Italy)
Lipari is the largest and most populated island in the Aeolian Archipelago, a UNESCO site, and a highly frequented touristic destination. As in many other insular settings, the low-lying coastal stretches in the E and NE sectors of Lipari are locally exposed to coastal erosion and flooding, enhanced by subsidence effects leading to local sea level rise. Most of these coastal sectors appear critical, being narrow and increasingly threatened by the risk of permanent inundation and beach disappearance. In this study, this setting is placed in the wider context of the decadal evolution of the main beaches, analysed through a multidisciplinary approach, which includes remote sensing techniques (aero-photogrammetry, unmanned aerial vehicle survey, and satellite data), offshore geophysical surveys (high-resolution multibeam bathymetry), and field observations. The results show a variable interaction in space and time between natural and anthropogenic factors in the long- and mid-term evolution of the studied coastal areas. Considering that part of the local economy at Lipari depends on beach tourism, proper future management is required in the view of natural risk reduction and in the light of future climate changes and related impacts
Sand Ridges on Rocky Coastal Platforms as Markers of Tsunami Impact: A Multi-Disciplinary Analysis along the Ionian Coast of Southern Apulia (Italy)
Along the Ionian coast of Southern Apulia, a sand ridge has been detected at the inner border of a wide, low-elevated rocky platform. A multi-disciplinary analysis was carried out to define the main geomorphological and sedimentological features of this dune-like coastal deposit, to clarify its nature as well as to obtain chronological constraints for its development. The geomorphological survey reveals that the sand ridge is about 40\u201360 m wide, reaching a maximum elevation of 3.9 m above m.s.l., whereas its thickness can be estimated between 1.0 and 2.8 m. The sand ridge is in some places associated with large-size boulders. Grain size analysis shows that it is made up of poorly sorted coarse-medium sands with a gravelly fraction, without significant sedimentary structures, as confirmed by Ground Penetrating Radar survey. The micro and macro-faunal assemblage sampled in the sand ridge can be related to shallow-water environments with Posidonia oceanica meadows occurring offshore. The development of the studied sand ridge can be ascribed to a tsunami event able to mix up very coarse bioclastic sands placed at submerged platforms, storm beach deposits covering the low-elevated coastal platform in patches, and possibly older tsunami deposits. Accelerator Mass Spectrometry radiocarbon age determinations on mollusc shells sampled from the sand ridge span from 929\u20131168 AD to 1707\u20131950 AD and cluster around the 18th\u201319th centuries, suggesting a possible association with a recent tsunami event. Data reported in the Euro-Mediterranean Tsunami Catalogue would indicate as the most likely event that one of the 25th April 1836, produced by a strong earthquake with its epicenter near Rossano village, on the Ionian coast of the Calabria region
Elite food between the Late Middle Ages and Renaissance. Some case studies from Latium
The study of plant and animal remains from archaeological sites provides important evidence about past human diets and habits: this includes species selection, food preparation, consumption and disposal practices. Furthermore, such information may also provide inferences about social status. Data from refuse disposal features identified in some elite contexts in central Italy – a high-status residence in Celleno Vecchio (Viterbo) and the Baglioni-Santacroce castle in Graffignano (Viterbo), both in northern Latium, as well as the Santi Quattro Coronati ecclesiastical complex in Rome – allow to explore, using archaeobotanical, archaeozoological and genetic data, some of the different ways in which people expressed wealth by means of food during a period between the late Middle Ages and Renaissance
- …