536 research outputs found

    The last five years of Big Data Research in Economics, Econometrics and Finance: Identification and conceptual analysis

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    Today, the Big Data term has a multidimensional approach where five main characteristics stand out: volume, velocity, veracity, value and variety. It has changed from being an emerging theme to a growing research area. In this respect, this study analyses the literature on Big Data in the Economics, Econometrics and Finance field. To do that, 1.034 publications from 2015 to 2019 were evaluated using SciMAT as a bibliometric and network analysis software. SciMAT offers a complete approach of the field and evaluates the most cited and productive authors, countries and subject areas related to Big Data. Lastly, a science map is performed to understand the intellectual structure and the main research lines (themes)

    Global trends in coronavirus research at the time of Covid-19: A general bibliometric approach and content analysis using SciMAT

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    Covid-19 represents the greatest challenge facing mankind today. In December 2019, several cases of pneumonia of unknown etiology were reported from China. This coronavirus infection subsequently identified as Covid-19 aroused worldwide concern. As a result, the scientific community has focused attention on Covid-19, as revealed by recent research reported in literature based on a holistic approach. In this regard, this study conducts a bibliometric analysis of coronavirus research in the literature with an emphasis on Covid-19 disease, using as a reference the publications in the Web of Science Core Collection from 1970 to 2020. This research analyzes 12,571 publications from 1970 to (April 18) 2020 by applying advanced bibliometric techniques in SciMAT bibliometric analysis software. The current research therefore provides a complete conceptual analysis of the main coronavirus types and strains in the literature by quantifying the main bibliometric performance indicators, identifying the main authors, organizations, countries, sources, and research areas, and evaluating the development of this field. Furthermore, a science map is constructed to understand the corresponding intellectual structure and main research lines (themes). SciMAT thereby offers a complete approach to the field and evaluates the main performance indicators related to coronavirus, with a focus on Covid-19. Finally, this research serves as a framework to strengthen existing research lines and develop new ones, establishing synergistic relationships that were not visible without the maps generated herein

    New biostratigraphic data from the Callovian-Oxfordian La Manga Formation, Neuquén Basin, Argentina: Evidence from an ammonite condensed level

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    The La Manga Formation constitutes most of the sedimentary record of the Callovian-Oxfordian in the Neuquén Basin. This stratigraphic unit represents the middle part of the Lotena Mesosequence, which is dominated by carbonates with interbedded shales, marls, and occasional sandstones. Based on detailed stratigraphic work in the stratotype section (La Manga Creek, Mendoza), the depositional environments and the sea-level history of the La Manga Formation have been interpreted. Petrographic and field observations led to identification of nine facies distributed in two informal units. Unit 1 was deposited on a outer ramp setting, while deposition of unit 2 took place in the intertidal-supratidal environments. A condensed level close to the base of unit 1 has yielded Rehmannia sp., Rehmannia cf. paucicostata (Tornq.) and Homoeoplanulites sp., from the Lower Callovian Bodenbenderi-Proximum Zones, and Peltoceratoides sp. and Rursiceras sp. from the Upper Callovian and also in the Lower Oxfordian Peltoceratoides-Parawedekindia Zone. The condensed level is overlain by a Middle Oxfordian succession characterized by Perisphinctes (?Arisphinctes) sp., Perisphinctes (?Kranaosphinctes) sp., Mirosphinctes sp., Perisphinctes (?Antilloceras) cf. prophetae Gygi & Hill., Perisphinctes (?Otosphinctes) sp., Perisphinctes (?Subdiscosphinctes) sp., and Perisphinctes (?Kranaosphinctes) cf. decurrens (Buck.) of the Perisphinctes-Araucanites Zone, which was correlated with the upper part of the Cordatum Standard Zone to the Transversarium Standard Zone, and probably to the lower part of the Bifurcatus Standard Zone. Unit 2 has yielded small Mirosphinctes sp., indicating an Oxfordian age. The sharp contact between the outer ramp facies of unit 1 and the overlying intertidal-supratidal facies of unit 2 can be interpreted as the result of an abrupt fall (forced regression) of the relative sea level during the end of Middle Oxfordian or Upper Oxfordian. These results could be used for comparison with other localities in the Neuquén Basin providing additional data for Lower Callovian-Middle Oxfordian deposits

    60 years of Business Intelligence: a Bibliometric Review from 1958 to 2017

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    Business Intelligence (BI) is being seen as a core activity in business, science, education or any field in which the use of intelligent software are vital to achieve their goals. The BI concept is also multidimensional, and it can be defined as a technology-driven process for analyzing data and presenting actionable information to support the organizational decisions. In this respect, the professionals involved in this area of knowledge are seeking to develop a culture of result orientation, focused on an effective decision-making and collaboration. Thus, the main aim of this contribution is to develop a bibliometric analysis to evaluate the performance and conceptual evolution of the authors and publications that are directly related to Business Intelligence

    Quantification of growth factors by using a new system for obtaining platelet-rich plasma

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    Objective: To verify the performance of a new method for obtaining platelet-rich plasma, while avoiding contamination of the sample during its processing. Study Design: Twenty healthy patients were selected, from whom 21 ml of blood was extracted. We then pro-Design: extracted. We proceeded to study the platelets and growth factors in basal blood after centrifuging the sample by using a new closed system for obtaining platelet-rich plasma (PRP). Results: After centrifuging the blood sample, double the amount of platelets as that found in basal blood was obtained. Of the four growth factors analyzed, only the factor similar to insulin (IGF) contained the same concentration after the centrifuge process. The platelet-derived growth factor (PDGF) and the vascular growth factor (VGF) were multiplied by six with respect to the basal values and disproportionately increased the levels of the transforming growth factor ? (TGF-?). Conclusions: The new closed method for obtaining PRP, after avoiding contamination of the sample following its use, offers levels of platelet concentrate and growth factors necessary for regeneration. © Medicina Oral S. L

    Diferencias en ansiedad escolar en función del sexo y curso académico en una muestra de estudiantes chilenos de educación básica

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    La literatura informa que la prevalencia de la ansiedad en edad infantil ha aumentado exponencialmente durante las últimas décadas, generando con ello la necesidad de monitorear permanentemente los estados emocionales principalmente en niños, y así evitar las dificultades de esta problemática. El objetivo fue establecer diferencias en ansiedad escolar en función del sexo y curso académico en estudiantes chilenos de educación básica. Para ello se contó con 3212 alumnos de 30 colegios de Ñuble en Chile, 1639 niñas y 1573 niños y edades entre 8 y 15 años (M=10.05 DT=1.01). La Ansiedad Escolar se evaluó con el Inventario de Ansiedad Escolar para Educación Primaria, que evalúa tres sistemas de respuesta (cognitiva, conductual y psicofisiológica) y cuatro factores situacionales (Ansiedad ante el castigo escolar, ansiedad ante la victimización, ansiedad ante la evaluación social y ansiedad ante la evaluación y fracaso escolar). Los resultados indican que las niñas presentan niveles de ansiedad significativamente mayores que los niños, aunque de pequeña magnitud. Respecto del curso académico, se observan diferencias estadísticamente significativas entre 4°  y 5°, entre 4° y 6° y entre 5° y 6° año. Estos resultados corroboran los obtenidos en investigaciones previas y alertan sobre el mantenimiento de ellos en el tiempo

    Identification and Visualization of the Conceptual Structure and Main Research Themes of Studies in Informatics and Control Journal from 2008 to 2019

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    Studies in Informatics and Control journal is a quarterly publication for all those involved in the field of Information Technology (IT). Studies in Informatics and Control journal provides important perspectives on topics relevant to IT, with an emphasis on useful applications in the most important areas of IT, and it is aimed at advanced practitioners and researchers in the field of IT. The core subjects covered by Studies in Informatics and Control journal are relating to innovative research and practice in Information Technology: IT use in control and management systems; integration of IT with control; application of IT in socio-economic systems and manufacturing processes, mainly. The current research conducts a bibliometric performance and conceptual structure analysis of Studies in Informatics and Control journal from 2008 to 2019. Firstly, the journal performance is analysed according to the data retrieved from the Web of Science Core Collection, putting the focus on the productivity of the authors, citations, countries, organizations and most relevant publications. Finally, the conceptual structure of the journal is analysed with bibliometric software tool SciMAT, identifying the main thematic areas that have been the object of research, their composition, relationship and evolution during the period analysed

    The complete nucleotide sequence of a Spanish isolate of <i>Citrus psorosis</i> virus: comparative analysis with other ophioviruses

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    The complete genomic sequence (11278 nt) of Citrus psorosis virus (CPsV), isolate P-121 from Spain, was determined and compared with those from isolate CPV-4 and from other ophioviruses. The three RNAs of P-121 had similar size and identical organization as those of CPV-4. The 24K and the RdRp proteins were potentially encoded in the viral complementary (vc) strand of RNA 1, the 54K protein potentially encoded in vcRNA 2 and the coat protein encoded in vcRNA 3. These four proteins from P-121 and CPV-4 had 87, 92, 93 and 94% amino acid identity, respectively, but only 22, 38, 25 and 33% identity with their homologous proteins from Mirafiori lettuce big vein virus (MLBVV), the only other ophiovirus completely sequenced. Biological and genetic differences between CPsV and MLBVV (and the other ophioviruses), would support their future allocation in different genera within a tentative family Ophioviridae.Instituto de Biotecnología y Biología Molecula

    Creación e implementación de Sistema Web y Aplicación móvil para la organización y publicación de una agenda de eventos de las empresas Nicaragüenses.

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    Presenta el desarrollo de un sistema web que organice la información de los eventos y actividades empresariales, de forma centralizada y clasificada por categorías de información facilitara a las empresas tener un mayor impacto en el mercado y a su vez retroalimentar por parte el sistema

    Pd-Catalyzed (3 + 2) Heterocycloadditions between Alkylidenecyclopropanes and Carbonyls: Straightforward Assembly of Highly Substituted Tetrahydrofurans

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acscatal.0c01827A Pd catalyst made from a Pd(0) source and a bulky biaryl phosphine ligand promotes highly efficient intramolecular (3 + 2) heterocycloadditions between alkylidenecyclopropanes (ACPs) and carbonyls. The annulations provide a straightforward access to fused polycyclic systems featuring β-methylene tetrahydrofuran moieties. DFT data support a pallada–ene process and shed light on the critical role of hemilabile interactions between the Pd center and the bulky biaryl phosphine. Significantly, these Pd(0) catalysts are also effective for promoting intermolecular formal cycloadditions between ACPs and trifluoromethyl ketones, thus providing for a direct entry to chiral tetrahydrofuran moieties (THFs) bearing trifluoromethyl–substituted carbonsThis work received financial support from the Spanish MINECO (SAF2016-76689-R, CTQ2017-84767-P), the Xunta de Galicia (ED431C 2017/19, 2015-CP082, Centro Singular de Investigación de Galicia accreditation 2019-2022, ED431G 2019/03, and a predoctoral Fellowship to E.d.C. and M.C.), CONICYT (grant to F.V.), and the ERDF, ERC (Adv. Grant 340055). The Orfeo–Cinqa network (CTQ2016-81797-REDC) is also acknowledgedS
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