Search results for "feature"
showing 10 items of 4091 documents
Cueva Antón: A multi-proxy MIS 3 to MIS 5a paleoenvironmental record for SE Iberia
2016
Overlying a palustrine deposit of unknown age (complex FP), and protected from weathering and erosion inside a large cave/rock-shelter cavity, the sedimentary fill of Cueva Antón, a Middle Paleolithic site in SE Spain, corresponds in most part (sub-complexes AS2-to-AS5) to a ca.3 m-thick Upper Pleistocene terrace of the River Mula. Coupled with the constraints derived from the deposit’s paleoclimatic proxies, OSL dating places the accumulation of this terrace in MIS 5a, and radiocarbon dates from the overlying breccia cum alluvium (sub-complex AS1) fall in the middle part of MIS 3; the intervening hiatus relates to valley incision and attendant erosion. The two intervals represented remain …
Preservation of modern and mis 5.5 erosional landforms and biological structures as sea level markers: A matter of luck?
2021
The Mediterranean Basin is characterized by a significant variability in tectonic behaviour, ranging from subsidence to uplifting. However, those coastal areas considered to be tectonically stable show coastal landforms at elevations consistent with eustatic and isostatic sea level change models. In particular, geomorphological indicators—such as tidal notches or shore platforms—are often used to define the tectonic stability of the Mediterranean coasts. We present the results of swim surveys in nine rocky coastal sectors in the central Mediterranean Sea using the Geoswim approach. The entire route was covered in 22 days for a total distance of 158.5 km. All surveyed sites are considered to…
Upper pleistocene interstratal piping-cave speleogenesis: The seso cave system (central pyrenees, northern spain)
2015
The Seso Cave System (SCS, South Central Pyrenees, Northeastern Spain) develops in poorly soluble marly interstratum between limestone beds of Eocene age. We propose an innovative and singular pseudokarstic speleogenetic model under vadose conditions based on cave morphological evidence, physicochemical and mineralogical characteristics of the Eocene marly host rock, U-Th dating of cave deposits, and local geological and geomorphological information. Eocene marls are shown to be sensitive to dispersion processes supported by their high clay content and the high concentration of sodium and low electrical conductivity in the seepage water. Runoff inside the cave results from water that infilt…
21. Abrupt change of El Niño activity off Peru during stage MIS 5e-d
2007
Abstract High-resolution proxy data for El Nino variability during the last glacial cycle were derived from a laminated marine sediment core from a region whose climatology and oceanography is strongly affected by ENSO variability. The proxies used are the seasurface temperature and the lithic flux from the continent onto the continental shelf that is largely controlled by the river flood discharge after strong El Nino rainfall in northern and northern central Peru. The focus of this paper is on an abrupt, possibly orbitally driven change of El Nino activity within marine isotope stage 5e. A similar sharp decline of El Nino activity is also observed during the middle of the Holocene intergl…
Eolian and fluvial sedimentation in the southwestern Sinai Mountains, Egypt: a record of flash floods during the late Pleistocene
2012
Wadis emerging from the southwestern Sinai Mountains (Egypt) westwards to the Gulf of Suez are filled by >40 m thick late Pleistocene sediments, which have been subsequently incised to bedrock after the Last Glacial Maximum (LGM). Sedimentation and erosion resulted from changes in the basin's hydrological conditions caused by climate variations. Sediment characteristics indicate distinct processes ranging from high to low energy flow regimes. Airborne material is important as a sediment source. The fills are associated with alluvial fans at wadi mouths at the mountain fronts. Each alluvial fan is associated and physically correlated with the respective sediment fill in its contributi…
Evolucion paleoambiental desde el Holoceno temprano hasta la actualidad del marjal de Almenara (Mediterráneo occidental)
2018
The main aim of this study is to characterize the different stages in the palaeoenvironmental evolution of the Almenara marsh, Spain, from the early Holocene to the present day. This marsh is one of the most important in Castellón province. Five cores extracted from the marsh underwent sedimentological analysis, micropalaeontological study (foraminifera, ostracods and gastropods) and 14C dating. The results show that before the maximum transgression of the Mediterranean during the Marine Isotope Stage 1 (5500 cal yr. BP dating in the Almenara marsh), the area was occupied by a brackish marsh (prior to the 8.2 ka event). During the middle Holocene, the regional sea level rise and later stabi…
Brand identity documentation: a cross‐national examination of identity standards manuals
2009
PurposeThe purpose of this paper is to identify the key features of an identity standards manual and assess the differences in the rules used for applying the brand to both low‐ and high‐context cultures, companies selling consumer goods and those selling services, and multinational and local companies.Design/methodology/approachThe methodology is based on the analysis of 341 identity standards manuals and on the analysis of three key features found in the manuals: contents, normative tone, and development.FindingsThe results divide the contents of the manual into two blocks: core and peripheral; and show that there are differences between the manuals of high‐ and low‐context cultures, comp…
Accelerating Causal Inference and Feature Selection Methods through G-Test Computation Reuse
2021
This article presents a novel and remarkably efficient method of computing the statistical G-test made possible by exploiting a connection with the fundamental elements of information theory: by writing the G statistic as a sum of joint entropy terms, its computation is decomposed into easily reusable partial results with no change in the resulting value. This method greatly improves the efficiency of applications that perform a series of G-tests on permutations of the same features, such as feature selection and causal inference applications because this decomposition allows for an intensive reuse of these partial results. The efficiency of this method is demonstrated by implementing it as…
Pyrolysis-gas chromatography/mass spectrometry of soil organic matter extracted from a Brazilian mangrove and Spanish salt marshes
2009
The soil organic matter (SOM) extracted under different vegetation types from a Brazilian mangrove (Pai Matos Island, São Paulo State) and from three Spanish salt marshes (Betanzos Ría and Corrubedo Natural Parks, Galícia, and the Albufera Natural Park, Valencia) was investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The chemical variation was larger in SOM from the Spanish marshes than in the SOM of the Brazilian mangroves, possibly because the marshes included sites with both tidal and nontidal variation, whereas the mangrove forest underwent just tidal variation. Thus, plant-derived organic matter was better preserved under permanently anoxic environments. Moreove…
Convolutional Neural Networks for Multispectral Image Cloud Masking
2020
Convolutional neural networks (CNN) have proven to be state of the art methods for many image classification tasks and their use is rapidly increasing in remote sensing problems. One of their major strengths is that, when enough data is available, CNN perform an end-to-end learning without the need of custom feature extraction methods. In this work, we study the use of different CNN architectures for cloud masking of Proba-V multispectral images. We compare such methods with the more classical machine learning approach based on feature extraction plus supervised classification. Experimental results suggest that CNN are a promising alternative for solving cloud masking problems.