18 research outputs found
Tendencias de la seguridad transaccional utilizada en las plataformas digitales de pago para mejorar la percepción de E-Commerce en El Salvador.
El enfoque central del presente trabajo es determinar las diferentes tendencias de seguridad transaccional utilizadas en plataformas digitales que permitan mejorar la percepción del e Commerce en El Salvador, bajo un contexto en el cual es fundamental para cualquier comercio digital o en proceso de digitalización informarse sobre los correctos procesos de pago, que le permita el reconocimiento como un sitio confiable y seguro. En el capÃtulo 1 se detallan las bases teóricas sobre las variables, el comercio electrónico y la seguridad transaccional, que permita conocer y realizar una conexión lógica de dependencia entre ellas que repercute en el éxito de los e-Commerce. El proceso de compra y venta a través de un e-Commerce en El Salvador se encuentra detallado en el capÃtulo 2, se desarrolla de manera teórica el comportamiento de los consumidores y de los comercios electrónicos en el mercado salvadoreño. A demás se desarrolla la base jurÃdica que enmarca la legislatura que regula el comportamiento de los agentes involucrados en el proceso antes mencionado. El capÃtulo 3 presenta una propuesta que utiliza diferentes estrategias de mercadeo para promover y mejorar la apariencia de los e-Commerce, se desarrolla paso a paso los elementos del Marketing Mix con un enfoque de reeducación para los consumidores a través de campañas de información. Que los comercios electrónicos utilicen las herramientas de la seguridad transaccional es de suma importancia, pero es más relevante que los e-Commerce puedan comunicar y educar a los usuarios sobre este tema y esto sea aprovechado como una estrategia para mejorar el posicionamiento y percepción de la marca
Lames, lamelles et éclats : un cas de variabilité dans la réalisation de l’outillage à l’aube de la transition Paléolithique moyen–supérieur en Italie
Les Néanderthaliens ont laissé diverses séries de preuves de culture, juste avant la transition Paléolithique moyen–Paléolithique supérieur en Europe. Parmi ces preuves, la production d’objets lithiques joue un rôle clé dans la détection d’affiliations possibles (ou d’absence d’affiliation) avec les techno-complexes trouvés durant les quelques millénaires avant l’expansion à grande échelle du Proto-Aurignacien. La phase cruciale a été enregistrée au Nord de l’Italie où, aux alentours de 44–45 ka cal BP, les derniers Néanderthaliens utilisaient encore la technique de débitage Levallois, en même temps que la technique adoptée sur différents sites de la région méditerranéenne centrale, en particulier à la Grotta di Fumane, qui fournit la preuve présentée dans cet article. La technique de production utilisée a pour conséquence différents niveaux de variabilité en ce qui concerne la production de lames quelquefois pointues et l’usage d’un écaillage centripète récurrent à la fin de la séquence de réduction, outre les structures volumétriques Discoïdes et lamellaires. Cette variabilité ne l’emporte pas sur la tendance à l’utilisation d’ébauches de taille Levallois allongées et autres sous-produits pour fabriquer des objets retouchés, tels que grattoirs et pointes simples ou convergents. Une interruption de cet usage, apparemment bien rodé, de la méthode unipolaire Levallois est enregistrée dans l’Uluzzien, où des éclats et nucléus ont été confectionnés en utilisant la modalité centripète, à la place de la précédente.Neanderthals left diverse sets of cultural evidence just before the Middle–Upper Palaeolithic transition in Europe. Within this evidence, the production of lithic implements plays a key role in detecting possible affiliations (or lack thereof) with the techno-complexes that occurred during the few millennia before the large-scale spread of the Proto-Aurignacian. This crucial phase has also been recorded in the North of Italy, where around 44–45 ky cal BP, the last Neanderthals were still using the Levallois knapping technique, in common with the technology adopted at several sites in the central Mediterranean region. A similar picture is seen at the Grotta di Fumane, which provides the evidence presented in this paper. The production technology employed produced different levels of variability with respect to the production of blades, sometimes pointed, and the use of recurrent centripetal flaking at the end of the reduction sequence, in addition to bladelet and Discoidal volumetric structures. This variability does not outweigh the dominant tendency towards the use of elongated Levallois blanks and other by-products for shaping into basic retouched tools such as simple or convergent scrapers and points. A break from this apparently well-rooted use of the unipolar Levallois method is recorded in the Uluzzian where, instead, flakes and cores were made using the centripetal modality.</p
The bulb retouchers in the Levant: New insights into Middle Palaeolithic retouching techniques and mobile tool-kit composition.
In this paper we describe two assemblages of flint retouchers or "bulb retouchers" retrieved from Nesher Ramla and Quneitra, two Middle Palaeolithic, open-air sites in the Levant. The site of Nesher Ramla yielded the largest assemblage of bulb retouchers (n = 159) currently known, allowing a detailed investigation of this poorly known phenomenon. An extensive experimental program and use-wear analysis enabled us to characterize the different sets of traces related to the retouching activity and to identify different motions applied by the knappers in the course of this action. In both sites, blanks used as bulb retouchers were almost exclusively retouched items, with a special emphasis on convergent morphotypes in Nesher Ramla. The use of retouched items as bulb retouchers is a common trait over different time spans and geographical areas. Our data suggests that bulb retouchers were versatile, multi-purpose tools with a long use-life, transported over long distances as components of the hunter-gatherer mobile tool kit. The high frequencies of bulb retouchers within some archaeological units of Nesher Ramla appear to be connected to the highly curated nature of the lithic assemblages, in turn reflecting a high mobility of the human groups that produced them
Effect of the support properties on the preparation and performance of platinum catalysts supported on carbon nanofibers
Utilità dell'elaborazione digitale nell'integrazione di metodiche di imaging nella diagnostica delle epatopatie.
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Grotta di Fumane. Risultati della campagna di scavo e ricerche 2012
La campagna di scavo 2012 a Grotta di Fumane, aperta dal 3 Luglio al 29 Settembre, si è incentrata sul settore atriale occidentale della cavità , interessando un'area di circa 12 m ² , nel settore predisposto nel 2008. Gli scavi, che si sono concentrati sul livello musteriano A9, sono stati diretti dell'Università degli Studi di Ferrara in concessione ministeriale, con il supporto di numerosi studenti e ricercatori provenienti da diversi atenei. La ricerca ha beneficiato del supporto finanziario di: Comunità Montana della Lessinia – Parco Naturale Regionale della Lessinia, Comune di Fumane, National Geographic Society, Impresa Costruzioni e Restauro Roberto Gardina, Max Plank Institute for Evolutionary Anthropology, Banca di Credito Cooperativo della Valpolicella, Albino Armani winegrovers. Il supporto logistico è stato fornito dal Comune di Fumane
Lactoferrin Inhibition of the Complex Formation between ACE2 Receptor and SARS CoV-2 Recognition Binding Domain
The present investigation focuses on the analysis of the interactions among human lactoferrin (LF), SARS-CoV-2 receptor-binding domain (RBD) and human angiotensin-converting enzyme 2 (ACE2) receptor in order to assess possible mutual interactions that could provide a molecular basis of the reported preventative effect of lactoferrin against CoV-2 infection. In particular, kinetic and thermodynamic parameters for the pairwise interactions among the three proteins were measured via two independent techniques, biolayer interferometry and latex nanoparticle-enhanced turbidimetry. The results obtained clearly indicate that LF is able to bind the ACE2 receptor ectodomain with significantly high affinity, whereas no binding to the RBD was observed up to the maximum “physiological” lactoferrin concentration range. Lactoferrin, above 1 µM concentration, thus appears to directly interfere with RBD–ACE2 binding, bringing about a measurable, up to 300-fold increase of the KD value relative to RBD–ACE2 complex formation
Grotta di Fumane. Indagini sul Musteriano finale (2010-2011)
La campagna di scavi 2012 a Grotta di Fumane si è svolta dal 3 Luglio fino al 29 Settembre e si è incentrata nel settore atriale occidentale della cavità per un'area di circa 12 m2, riprendendo il lavoro che nel medesimo settore era terminato nel 2008; gli scavi, che hanno interessato principalmente il livello denominato A9, attribuito a gruppi Neandertaliani, si sono svolti sotto la direzione del Dott. Marco Peresani dell’Università degli studi di Ferrara, coadiuvato da numerosi studenti e ricercatori provenienti da diversi atenei che si sono alternati nei mesi di scavo