Search results for "Ephemera"
showing 10 items of 68 documents
Channel forms recovery in an ephemeral river after gravel mining (Palancia River, Eastern Spain)
2017
[EN] During the 1970s, the Palancia River was intensively affected by gravel mining instream. This activity completely destroyed the fluvial forms, devastating the original wandering pattern. At the end of the 1980s, gravel mining ceased and the river started a process of recovery, only altered by several clearing operations. The aim of this work is to describe these processes of change, analyzing the river's morphosedimentary conditions through a GIS analysis of aerial photographs previous to, simultaneous with, and subsequent to the intense gravel mining activity. Results explain the current difficulties of some ephemeral rivers to recover their original forms, because of the sediment and…
History of ancient megathrust earthquakes beneath metropolitan Tokyo inferred from coastal lowland deposits
2018
Abstract Metropolitan Tokyo is located directly above a subduction zone that has generated two megathrust earthquakes in the past 300 years. However, the timing of older megathrusts on this margin is poorly understood. In this study, we aim to constrain the timings of past megathrust earthquakes, using coastal stratigraphy, paleoecology, radiocarbon dating and archaeological records from coastal lowlands. An investigation of 13 boreholes in the southern coastal area of metropolitan Tokyo found evidence for 4 m of uplift in a 6000-year period. However, we found that net vertical displacement in the last 1000 years is approximately zero. Results suggest that preservation of usually ephemeral …
Uneven Data Quality and the Earliest Occupation of Europe—the Case of Untermassfeld (Germany)
2017
AbstractThe database regarding the earliest occupation of Europe has increased significantly in quantity and quality of data points over the last two decades, mainly through the addition of new sites as a result of long-term systematic excavations and large-scale prospections of Early and early Middle Pleistocene exposures. The site distribution pattern suggests an ephemeral presence of hominins in the south of Europe from around one million years ago, with occasional short northward expansions along the western coastal areas when temperate conditions permitted. From around 600,000-700,000 years ago Acheulean artefacts appear in Europe and somewhat later hominin presence seems to pick up, w…
Temperature differences associated with colour do not determine where the acorn ant Temnothorax crassispinus (Hymenoptera: Formicidae) chooses to nest
2021
Temperature is an important factor for invertebrates. Social insects build nests, which along with their ability to thermoregulate, provide shelter from extreme temperatures. However, for many species of ants the most common method of controlling the temperature inside a nest is to choose a suitable nest site. During a fi eld experiment, the choice of nest site by the acorn ant Temnothorax crassispinus, a species which lives in coniferous and mixed forests, was studied. It typically occupies ephemeral nest sites and can move to a new nest site several times in one season. It was predicted that in early spring, dark coloured nest sites would be warmer and thus more frequently occupied by ant…
High within- and between-trunk variation in the nematoceran (Diptera) community and its physical environment in decaying aspen trunks
2012
Dead wood is a primary habitat for a large number of insects, including species from many nematoceran (Diptera) groups. The species living in dead wood must be adapted to the ephemeral and ever-changing nature of their substrate. There is a growing body of knowledge about the effects of dead wood quality and the surrounding landscape on the saproxylic beetle community, but we know very little about the other saproxylic insects. Moreover, we know only very little about the variation in the insect community between different parts of decaying wood pieces. Using emergence traps, we studied the saproxylic nematoceran communities occupying different parts of decaying fallen aspen trunks in a bor…
L'immagine della monarchia e il ruolo del Senato nelle feste per S. Rosalia a Palermo: apparati, architetture e spazio urbano nel XVII secolo
2012
La festa barocca a Palermo costituisce l’alter ego effimero e occasionale del processo di monumentalizzazione, graduale e complesso, della città: entrambi obbediscono alle stesse esigenze di ufficialità e magnificenza, da soddisfare obbligatoriamente nell’ottica di una città capitale. L’autorevole regista delle grandi manifestazioni ufficiali è il Senato palermitano, al quale come massima istituzione della città è affidata in genere la responsabilità sia dell’organizzazione materiale, sia dell’elaborazione culturale del programma celebrativo, in particolare della festa annuale in onore di S. Rosalia. In Palermo the baroque festival is the ephemeral and occasional alter ego of monumentalisat…
Daily streamlow prediction with uncertainty in ephemeral catchments using the GLUE methodology
2009
Abstract The Generalised Likelihood Uncertainty Estimation (GLUE) approach is presented here as a tool for estimating the predictive uncertainty of a rainfall–runoff model. The GLUE methodology allows to recognise the possible equifinality of different parameter sets and assesses the likelihood of a parameters set being acceptable simulator when model predictions are compared to observed field data. The results of the GLUE methodology depend greatly on the choice of the likelihood measure and on the choice of the threshold which determines if a parameters set is behavioural or not. Moreover the sampling size has a strong influence on the uncertainty assessment of the response of a rainfall–…
Rilievo di un ephemeral gully nell’area sperimentale di Sparacia mediante una tecnica fotografica
2016
Nella memoria sono riportati i risultati dell’applicazione di una tecnica imagebased per il monitoraggio di un ephemeral gully formatosi nel gennaio 2015 nell’area sperimentale di Sparacia. Nel gully, lungo 54 m, sono state individuate 24 sezioni trasversali che sono state rilevate in campo mediante l’uso di un profilometro. L’indagine ha inoltre previsto la realizzazione di un modello tridimensionale del terreno (DTM) ottenuto con l’impiego di un numero elevato di fotografie della stessa scena acquisite da differenti punti di vista (Tecnica “Structure-From Motion” SFM e “Multi-View-Stereo MVS). Dal DTM tridimensionale (3D) e dal modello 2.5D sono stati estratti i profili delle sezioni tras…
Archives and documents in the digital age
2017
Este artículo se propone reflexionar sobre algunas de las características del nuevo orden digital. En particular, se centra en las mutaciones que afectan a los conceptos de archivo y documento, así como a sus rasgos más destacados. Partiendo del hecho de que estos registros son fundamentales para cualquier estudioso del pasado, indaga sobre las consecuencias de su desmaterialización. Se examina el significado de ese espacio en algunas de sus dimensiones y se subraya la evidente paradoja que supone conservar y estudiar objetos o datos que son efímeros por naturaleza y que, en su mayoría, nacieron para morir rápidamente. The paper aims to examine and explore on some of the characteristics of …
Measuring rill erosion at plot scale by a drone-based technology
2015
The traditional direct method (i.e. metric ruler and rillmeter) of monitoring rill erosion at plot scale is time consuming and invasive since it modifies the surface of the rilled area. Measuring rill features using a drone-based technology is considered a non-invasive method allowing a fast field relief. In the experimental Sparacia area a survey by a quadricopter Microdones md4-200 was carried out and this relief allowed the generation of a Digital Elevation Model (DEM), with a mesh size of 1 cm and a resolution elevation equal to 2 mm, for three plots (L, G and C) affected by rill erosion. At first for the experimental L plot, which is 44 m long, the rill features were surveyed by a “man…