Search results for "Hf"
showing 10 items of 909 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…
The behaviour of zirconium, hafnium and rare earth elements during the crystallisation of halite and other salt minerals
2017
Abstract Halite crystals from Messinian and Tortonian evaporites from Sicily and Spain and current precipitated halite crystals and the relative parent brines (active evaporation systems) were investigated in order to evaluate the Zr, Hf and Rare Earth Element (REE) behaviour. Halite crystallisation from evaporating brines fractionates Zr, Hf and REE through a two-step process. During the first step, dissolved complexes of studied elements are scavenged onto the surfaces of crystallising halite. During the second step, elements are co-precipitated into the crystal lattice as it grows. The first step mechanism is determined by the dissolved REE speciation. In saltworks where carbonate-REE co…
Zr/Hf ratio and REE behaviour: A coupled indication of lithogenic input in marginal basins and deep-sea brines
2019
Abstract The distribution of dissolved Zr, Hf and Rare Earth Elements (yttrium and lanthanides, hereafter referred to as REE) in the Eastern Mediterranean seawater column was measured in the Kryos basin to evaluate the lithogenic contribution from both Nile River and Sahara and Arabian desert dust. We found dissolved Zr/Hf ratios below the signature of crustal rocks and chondrites; a phenomenon likely driven by the dissolution of the Mn-rich coating of atmospheric dust particles delivered from the desert. In deeper waters, Zr/Hf ratios are clustered close to the signature of crustal rocks and chondrites according to the different Zr and Hf dissolved speciation. The Zr/Hf ratio observed in t…
Validation of HF radar sea surface currents in the Malta-Sicily Channel
2019
Abstract A network of High-Frequency radar (HFR) stations runs operationally in the Malta-Sicily Channel (MSC), Central Mediterranean Sea, providing sea surface current maps with high temporal (1 h) and spatial (3 × 3 km) resolutions since August 2012. Comparisons with surface drifter data and near-surface Acoustic Doppler Current Profiler (ADCP) observations, as well as radar site-to-site baseline analyses, provide quantitative assessments of HFR velocities accuracy. Twenty-two drifters were deployed within the HFR domain of coverage between December 2012 and October 2013. Additionally, six ADCP vertical current profiles were collected at selected positions during a dedicated field survey.…
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…
Mussel Farming and Its Potential in the Baltic Sea
2017
Abstract The paper covers research findings on mussel farming and the analysis of current situation in mussel farming in the Baltic Sea. The mussel farming has a development potential in the Baltic Sea region. Some developers have chosen progressive activities to achieve the aim. For example, in Sweden the development of mussel farming is suggested as one of the instruments for reducing eutrophication. Several countries in the Baltic Sea region are in the beginning phase of the mariculture development. The following research methods were used in the research: studies of scientific publications, case studies and document studies on some important factors impeding the development of mussel fa…
Response of the N and P cycles of an old-growth montane forest in Ecuador to experimental low-level N and P amendments
2010
Abstract Atmospheric nitrogen (N) and phosphorus (P) depositions are expected to increase in the tropics as a consequence of increasing human activities in the next decades. In the literature, it is frequently assumed that tropical montane forests are N-limited, while tropical lowland forests are P-limited. In a low-level N and P addition experiment, we determined the short-term response of N and P cycles in a north Andean montane forest on Palaeozoic shists and metasandstones at an elevation of 2100 m a.s.l. to increased N and P inputs. We evaluated experimental N, P and N + P additions (50 kg ha −1 yr −1 of N, 10 kg ha −1 yr −1 of P and 50 kg + 10 kg ha −1 yr −1 of N and P, respectivel…
Downscaling hydrodynamics features to depict causes of major productivity of Sicilian-Maltese area and implications for resource management
2018
Abstract Chlorophyll- a ( CHL-a ) and sea surface temperature ( SST ) are generally accepted as proxies for water quality. They can be easily retrieved in a quasi-near real time mode through satellite remote sensing and, as such, they provide an overview of the water quality on a synoptic scale in open waters. Their distributions evolve in space and time in response to local and remote forcing, such as winds and currents, which however have much finer temporal and spatial scales than those resolvable by satellites in spite of recent advances in satellite remote-sensing techniques. Satellite data are often characterized by a moderate temporal resolution to adequately catch the actual sub-gri…
A ricardian analysis of the impact of climate change on permanent crops in a mediterranean region
2019
This is the first study which explores the impact of climate change in Sicily, a small Mediterranean region of Southern Europe. According to research, Mediterranean area has shown large climate shifts in the last century and it has been identified as one of the most prominent “Hot-Spots” in future climate change projections. Since agriculture is an economic activity which strongly depends on climate setting and is particularly responsive to climate changes, it is important to understand how such changes may affect agricultural profitability in the Mediterranean region. The aim of the present study is to assess the expected impact of climate change on permanent crops cultivated in Sicilian r…
Phylogenetic placement of Cailliella praerupticola (Melastomataceae), a rare, monospecific lineage from Guinea, West Africa
2021
The genus Cailliella includes a single species, C. praerupticola, restricted to a sandstone plateau region in Coyah, Dubreka, Forecariah and Kindia Prefectures, Guinea, West Africa. Until its rediscovery in 2016, this species was known only by the type gathering made in 1937. We provide an emended description, photographs of living material, locality and habitat data, and a discussion of its conservation status. We further designate a lectotype for C. praerupticola. On the basis of morphology, Cailliella had been considered an isolated member of the tribe Melastomateae, possibly sister to Melastomastrum. We tested the classification of Cailliella by means of a phylogenetic analysis of C. pr…