Search results for "Alta"
showing 10 items of 1309 documents
¿Cómo afecta la innovación en la satisfacción y la lealtad hacia el establecimiento minorista?
2021
Resumen En el presente estudio, se examinó el concepto de innovación en el sector minorista y se definieron sus relaciones con otras variables, como la satisfacción y la lealtad, tradicionalmente vinculadas con el establecimiento minorista. Para lograr los objetivos planteados, se delimitó un modelo teórico sustentado en la literatura, que se contrastó mediante un estudio empírico utilizando un cuestionario estructurado ad hoc aplicado a una muestra de 510 clientes de establecimientos de alimentación. El análisis de los datos se desarrolló mediante la técnica de regresión por mínimos cuadrados parciales. Los resultados permiten proponer un conjunto de recomendaciones para la gestión, fundam…
HF radar for wind waves measurements in the Malta-Sicily Channel
2018
Abstract The CALYPSO HF radar network is a permanent and fully operational observing system currently composed of four CODAR SeaSonde stations. The system is providing real-time hourly maps of sea surface currents and waves data in the Malta-Sicily Channel. The present work aims to compare significant wave height measurements by HF Radar to wave data from numerical models and satellite altimeter. This is the first time that this set of wave data are analysed since the four HF radars were installed between 2012 and 2015. Results suggest that CODAR HF Radar wave data are a reliable source of wave information even in the case of extreme events, providing an avenue to improve and complete the o…
The geological roots of South America: 4.1 Ga and 3.7 Ga zircon crystals discovered in N.E. Brazil and N.W. Argentina
2015
International audience; We present new LA-ICP-MS in situ geochronological results for seven Eoarchean zircons dated at 3.7 Ga coming from Cretaceous ash layers of NW Argentina and one Hadean single crystal sampled within the São Francisco Craton in NE Brazil. This zircon comprises a zoned magmatic core dated at 4.1 Ga surrounded by a 1.9 Ga overgrowth related to Paleoproterozoic reworking. This Hadean age is consistent with previously published Nd model ages on orthogneisses from the same domain. These two results represent among the oldest geological witnesses discovered to date in South America, which demonstrates the occurrence of a primitive crust. The contrasting age patterns recorded …
Late Quaternary palaeoenvironmental reconstruction of sediment drift accumulation in the Malta Graben (central Mediterranean Sea)
2018
The Malta Graben is a deep tectonic depression in the Sicily Channel, bounded by NW-SE normal faults and filled by thick Pliocene-Quaternary deposits. A previous analysis of a giant piston core (LC09) from the Malta Graben had revealed a wide range of sedimentary features (carbonate turbidites, bioturbated mud and scours), although the chronostratigraphic constraint of the stacking pattern has remained elusive. After establishing a reliable chronological framework based on seven radiocarbon dates for a shorter core from the Malta Graben (ANSIC03-735), a down-core analysis of planktonic foraminifer and coccolith abundance, stable isotopes and sediment grain size was carried out. Since the la…
Depositional mechanism of the upper Pliocene-Pleistocene shelf-slope system of the western Malta Plateau (Sicily Channel)
2021
Abstract A high resolution seismic stratigraphic study of the western edge of the Malta Plateau (central Mediterranean Sea) was conducted to reconstruct the depositional mechanisms of the shelf-slope system since the end of the Messinian salinity crisis (MSC; 5.3 Ma). The accurate interpretation of a large grid of variable-resolution seismic reflection profiles (multichannel and Sub Bottom) allows us to identify and map a Plio-Quaternary sedimentary sequence overlying the Messinian evaporites. The stratal pattern of this sequence is the result of a clinoform prograding system that constitutes the internal structure of a sedimentary shelf developed in a ramp about 2° slope with bathymetries …
Novel sexual dimorphism in a new genus of Bathynellidae from Russia, with a revision of phylogenetic relationships
2019
Bathynellidae is the neglected family of Bathynellacea, a groundwater group of crus- taceans with 33 genera and 107 species described and almost half of them included in the `catch-all¿ genus Bathynella. Due to the morphological homogeneity of the spe- cies, the taxonomic uncertainties have accumulated over time. Therefore, to explore the phylogenetic relationships among taxa, a combined approach using morphologi- cal and molecular data is needed. In this paper, we performed a phylogenetic analysis based on partial sequences of COI and 18S including 30 species of Bathynellidae. This data set represents the most updated one, including a new genus and a new spe- cies (Altainella calcarata gen…
The late Pleistocene origin of the Italian and Maltese populations of Potamon fluviatile (Malacostraca: Decapoda): insights from an expanded sampling…
2017
Evidence available for most inland water and terrestrial organisms highlights the significant role played by southern Italy, Sicily and the Maltese islands as refuges during Pleistocene climatic fluctuations. However, to date, the hypothesis that these areas may have acted as Pleistocene refugia for the freshwater crab Potamon fluviatile has not been explicitly tested, and a recent origin of local P. fluviatile populations was proposed on the basis of a small set of analysed molecular data. We have thus expanded the currently available data set on the population genetic structure of P. fluviatile through dedicated samplings in Sicily (Italy, 18 specimens), the Maltese Islands (Malta, 15 spe…
Origin and distribution of desert ants across the Gibraltar Straits
2017
The creation of geographic barriers has long been suspected to contribute to the formation of new species. We investigated the phylogeography of desert ants in the western Mediterranean basin in order to elucidate their mode of diversification. These insects which have a low dispersal capacity are recently becoming important model systems in evolutionary studies. We conducted an extensive sampling of species belonging to the Cataglyphis albicans group in the Iberian Peninsula (IP) and the northern Morocco (North Africa; NA). We then combined genetic, chemical and morphological analyses. The results suggest the existence of at least three and five clades in the IP and NA, respectively, whose…
Pleistocene diversification in Morocco and recent demographic expansion in the Mediterranean pond turtle Mauremys leprosa
2016
Quaternary climatic oscillations and geographic barriers have strongly influenced the distribution and diversification of thermophilic species occurring in the Mediterranean Basin. The Western Mediterranean pond turtle, Mauremys leprosa, is widely distributed throughout the Iberian Peninsula, southern France and most of the Maghreb region, with two subspecies currently recognized. In this work, we used 566 samples, including 259 new individuals, across the species range, and sequenced two mitochondrial markers (cytochrome b gene and control region; 163 samples in a concatenated mtDNA dataset) and one nuclear intron (R35; 23 samples representing all identified sublineages) to study the evolu…
The role of the Strait of Gibraltar in shaping the genetic structure of the Mediterranean Grenadier, Coryphaenoides mediterraneus, between the Atlant…
2017
24 pages, 4 figures, 4 tables, supplementary information https://dx.doi.org/10.1371/journal.pone.0174988.-- Data Availability: The mtDNA COI sequences can be accessed at BOLD systems through the sample ID: ME-9911; ME-11972; ME-13727; GLF011. New mtDNA COI sequences can be accessed at GenBank by the accession numbers KY345206 - KY345398. GenBank accession numbers for close related species of C. mediterraneus are: Coryphaenoides striaturus - KX656427.1, KX656428.1; Coryphaenoides murray - KX656411.1, KX656410.1; Coryphaenoides carapinus - KX656382.1, KX656381.1; Coryphaenoides brevibarbis - KX656377.1, KX656376.1, KX656375.1. An alignment in fasta with all the haplotypes and respective frequ…