Paleogene evolution of the External Rif Zone (Morocco) and comparison with other western Tethyan margins

The Paleogene evolution of theNWmargin of the African Plate (Western External Rif Zone)was studied by means of multidisciplinary analyses of twenty-one stratigraphic logs, including tectofacies recognition, petro-mineralogical results, and thicknesses analysis. Four stratigraphic intervals were recognized separated by three unconformities coarsely aligned with the Cretaceous–Paleogene, Eocene–Oligocene and Oligocene–Miocene boundaries, respectively. Tectofacies appear from the late Ypresian being more frequents from the Oligocene as the tectonic activity increases. The petrology of detrital suites indicates recycled orogen-derived sediments, with quartz supplied from metamorphic rocks of the Atlas orogen and/or the African craton. On the basis ofMesozoic claymineral assemblages reported in the literature, the clay mineralogy of mudstones suggests upper Jurassic to upper Cretaceous terrains from the Internal Intrarif as the main source area of the Paleocene–Eocene successions, with sediment provenance reversion during the Oligocene and additional contribution of Paleocene to lower Eocene suites. The different displacement capability of the identified aluminic-magnesic claymineralogy enabled to deduce the relative proximity of the source area. These findings point out a complex sedimentary evolution characterized by a mixture of different lithotypes dating back to upper Jurassic. X-ray parameters helped to identify evidences of synsedimentary tectonics overprinting the inheritedmineralogy during some periods with weak burial diagenesis at most. During the Paleogene a foreland basin is formed mainly in theMesorif and Prerif sub-domains. This foredeep was represented by two ‘sub-geosynclines’ separated by a relative bulge located in the ExternalMesorif. The Internal Intrarif could represent the relative orogenic front, advancing on the External Intrarif. The Eocene forebulge was located in the Ridges Domain, while the Gharb Basin was the backbulge of the system. During the Oligocene the depocentral area migrated southward and a homogeneization of thicknesses took also place in thewholemargin. In this newconfiguration, the foredeep would be located in the External Mesorif (previously a relative bulge) while the Ridges Domain and the Gharb Basin continued to act as the systemforebulge and backbulge, respectively. A comparisonwith the Paleogene evolution of otherwestern Tethys externalmargins (Betic Chain, Tunisian Tell, SicilianMaghrebids, and Apennines) has revealed more similarities than differences. The effects of the Eo-Alpine tectonics are recognized everywhere even if they decrease both from N to S, and fromWto E in the different considered margins. The evolution of the compared margins shows a common pre-foredeed (Paleocene-Eocene) and beginning of foredeep (Oligocene) stages in the foreland basins.PID2020-114381GB-I00 research project (Spanish Ministry of Education and Science)

Pilas y acumuladores comerciales (y II). Sistemas secundarios y especiales

Con este segundo capítulo se completa esta pequeña serie dedicada a pilas y acumuladores comerciales. Se abordan aquí con cierta extensión los sistemas especiales, de gran interés y poco conocidos generalmente. El resto del capítulo se dedica a acumuladores

Claves para la promoción de ventas en función de las categorías de productos de compra frecuente

Las promociones detallistas tienen como respuesta más directa el incremento a corto plazo de las ventas del producto promocionado. El cambio de marca ha sido el efecto que tradicionalmente se ha considerado que explicaba el mayor porcentaje del incremento de ventas. Investigaciones recientes han encontrado que el efecto de la aceleración de compra y el incremento de la cantidad comprada tienen mayor peso en explicar dichas ventas. Estos fenómenos se pueden producir debido a las características de la categoría (como el precio, penetración y frecuencia de compra de la categoría, así como el efecto almacenamiento en los hogares de los consumidores) así como a las características propias de las referencias (cuota de mercado y precio de las marcas). En este trabajo analizamos mediante los datos de un panel de detallistas que recoge las ventas obtenidas en promoción, si las distintas categorías de productos producen efectos diferenciadores en las ventas de los mismos.Retail promotions have a direct response to short-term increase in sales of the promoted product. Brand change has traditionally been identified as the primary explanation for sale increase. However, recent research has put more emphasis on speedy consumption and the increase in the amount purchased as the basic explanations for the increase in sales. These phenomena may occur due to the characteristics of the category (such as price, market penetration and purchase frequency category and the storage effect in the homes of consumers), as well as the characteristics of the references products (market share and brand price). In this paper we analyze the data from a retail panel, to investigate if the sales promotion of different product categories produces a differentiator effect amongst them

Supervised contrastive learning over prototype-label embeddings for network intrusion detection

Producción CientíficaContrastive learning makes it possible to establish similarities between samples by comparing their distances in an intermediate representation space (embedding space) and using loss functions designed to attract/repel similar/dissimilar samples. The distance comparison is based exclusively on the sample features. We propose a novel contrastive learning scheme by including the labels in the same embedding space as the features and performing the distance comparison between features and labels in this shared embedding space. Following this idea, the sample features should be close to its ground-truth (positive) label and away from the other labels (negative labels). This scheme allows to implement a supervised classification based on contrastive learning. Each embedded label will assume the role of a class prototype in embedding space, with sample features that share the label gathering around it. The aim is to separate the label prototypes while minimizing the distance between each prototype and its same-class samples. A novel set of loss functions is proposed with this objective. Loss minimization will drive the allocation of sample features and labels in embedding space. Loss functions and their associated training and prediction architectures are analyzed in detail, along with different strategies for label separation. The proposed scheme drastically reduces the number of pair-wise comparisons, thus improving model performance. In order to further reduce the number of pair-wise comparisons, this initial scheme is extended by replacing the set of negative labels by its best single representative: either the negative label nearest to the sample features or the centroid of the cluster of negative labels. This idea creates a new subset of models which are analyzed in detail. The outputs of the proposed models are the distances (in embedding space) between each sample and the label prototypes. These distances can be used to perform classification (minimum distance label), features dimensionality reduction (using the distances and the embeddings instead of the original features) and data visualization (with 2 or 3D embeddings). Although the proposed models are generic, their application and performance evaluation is done here for network intrusion detection, characterized by noisy and unbalanced labels and a challenging classification of the various types of attacks. Empirical results of the model applied to intrusion detection are presented in detail for two well-known intrusion detection datasets, and a thorough set of classification and clustering performance evaluation metrics are included.Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación - Fondo Europeo de Desarrollo Regional (grant RTI2018-098958-B-I00

Why do papers from international collaborations get more citations? A bibliometric analysis of Library and Information Science papers

Scientific activity has become increasingly complex in recent years. The need for international research collaboration has thus become a common pattern in science. In this current landscape, countries face the problem of maintaining their competitiveness while cooperating with other countries to achieve relevant research outputs. In this international context, publications from international collaborations tend to achieve greater scientific impact than those from domestic ones. To design policies that improve the competitiveness of countries and organizations, it thus becomes necessary to understand the factors and mechanisms that influence the benefits and impact of international research. In this regard, the aim of this study is to confirm whether the differences in impact between international and domestic collaborations are affected by their topics and structure. To perform this study, we examined the Library and Information Science category of the Web of Science database between 2015 and 2019. A science mapping analysis approach was used to extract the themes and their structure according to collaboration type and in the whole category (2015-2019). We also looked for differences in these thematic aspects in top countries and in communities of collaborating countries. The results showed that the thematic factor influences the impact of international research, as the themes in this type of collaboration lie at the forefront of the Library and Information Science category (e.g., technologies such as artificial intelligence and social media are found in the category), while domestic collaborations have focused on more well-consolidated themes (e.g., academic libraries and bibliometrics). Organizations, countries, and communities of countries must therefore consider this thematic factor when designing strategies to improve their competitiveness and collaborate

Aesthetics and relationship quality. An application to online music services among young europeans

Más allá de las investigaciones que examinan la influencia del aspecto cognitivo (por ejemplo, la usabilidad) de los sitios web sobre la calidad relacional, el examen de su evaluación afectiva también se hace necesaria. En este sentido, no existe actualmente un consenso relativo en torno a la influencia de la estética del sitio web en el grado de adecuación de una relación para satisfacer las necesidades del usuario. Proponemos en este estudio un modelo integrador que plantea una red de relaciones donde: (a) la confianza y la satisfacción se relacionan directamente con el compromiso afectivo; y (b) la estética –concebida como la apariencia agradable a la vista– cuasimodera la calidad de relación. El modelo de medida y estructural propuestos son analizados empleando Análisis Factorial Confirmatorio (AFC) y Partial Least Squares (PLS), respectivamente. Se señalan las principales conclusiones del estudio y sus implicaciones para la dirección de marketing. (1) El modelo de medida es válido; su validez convergente y discriminante es aceptada. (2) Nuestro estudio modela y confirma (2.1) los efectos directos de la estética sobre la calidad de relación; y (2.2) los efectos moderadores de la estética sobre las relaciones entre la satisfacción y el compromiso y la confianza y el compromiso. En definitiva, nuestra investigación destaca la relevancia de la estética del sitio web de descarga de música; por un lado, mejora las experiencias del usuario durante sus interacciones con el sitio web; y, por otro lado, se erige en un determinante significativo del grado de compromiso afectivoBeyond the studies on the influence of the cognitive aspects (e.g, usability) of websites on relational quality, there is a need to examine their affective evaluation. To this date, there is no consensus about the influence of website aesthetics in the degree of suitability of a relation to meet the user's needs. We propose herein an integrative model encompassing a network of relationships where: (1) trust and satisfaction correlate directly with affective commitment; and (2) aesthetics (defined as visual appeal from a beauty point of view) acts as a quasi-moderator of relationship quality. The proposed measurement and structural models are analysed by Confirmatory Factorial Analysis (CFA) and Partial Least Squares (PLS), respectively. The following conclusions of our work are discussed in the context of their significance for marketing direction: (1) The measurement model is valid: its validity –both convergent and discriminatory– is accepted; (2) Our study models and confirms (2.1) the direct effects of aesthetics on relationship quality; and (2.2) the moderating effects of aesthetics on the relationships between satisfaction and commitment as well as trust and commitment. In short, our research highlights the relevance of music website aesthetics. On the one hand, it improves the user's experience during his/her interaction with websites. On the other, it becomes a critical determinant of the degree of affective commitmen

Cristales líquidos: bases de su comportamiento I

En este primer artículo, de una serie de tres,se presentan las principales clases de cristales líquidos existentes, así como las configuraciones más usuales de trabajo. Se presentan algunas formas de fabricación de células, y se dan las bases físicas de su comportamiento óptico, eléctrico y magnético. Finalmente se ofrece una panorámica global de sus principales aplicaciones

Nuevos materiales para nuevas tecnologías electrónicas

La Electrónica y la Química Orgánica, que han sido campos separados durante muchos años, se están acercando rápidamente en la actualidad. De un tiempo a esta parte han surgido bastantes áreas de interés común, en las que ambas ciencias aparecen como complementarias. Este trabajo se concentra en tres de estas áreas: la primera, adhesivos y compuestos afines, es un ejemplo clásico de los materiales que han sido desarrollados por la Química Orgánica para usos electrónicos; la segunda, cristales líquidos, es una reciente contribución a la Electrónica en la cual se sigue investigando intensamente; la tercera, semiconductores orgánicos, predice una relación aún más próxima de estos dos campos a corto y medio plazo

Biestabilidad óptica: un nuevo camino para el láser

En este artículo se analiza un nuevo tipo de dispositivo óptico que, basándose en conceptos análogos a los ya empleados en la tecnología del láser, ofrece un amplio campo de posibilidades de aplicación. Su objetivo es puramente de revisión del estado actual del tema, ofreciéndose los avances más significativos conseguidos hasta la fecha

Cristales líquidos: Nuevas aplicaciones (y III)

En este último artículo de la serie se presentan algunos desarrollos que ofrecen nuevas posibles aplicaciones de los cristales líquidos. El énfasis se da a moduladores, deflectores, biestables ópticos y moduladores optoópticos