ϕ2\phi^2 as Dark Matter

In this paper we consider $\phi^2$ scalar field potential as a candidate to dark matter. If it is an ultralight boson particle, it condensates like a Bose-Einstein system at very early times and forms the basic structure of the Universe. Real scalar fields collapse in equilibrium configurations that oscillate in space-time (oscillatons).The cosmological behavior of the field equations are solved using the dynamical system formalism. We use the current cosmological parameters as constraints for the present value of the scalar field. We reproduce the cosmological predictions of the standard $\Lambda$CDM model with this model. Therefore, scalar field dark matter seems to be a good alternative to cold dark matter nature.Comment: Accepted for publication in MNRAS 11 pages, 7 figure

Ultra light bosonic dark matter and cosmic microwave background

In this paper, we consider the hypothesis in which a species of ultra light bosonic dark matter (ULBDM) with mass $m_{B}\sim 10^{-22}$ eV could be the dominant dark matter (DM) in the Universe. As a first approach we work in the context of kinetic theory, where ULBDM is described by the phase space distribution function whose dynamics is dictated by the Boltzmann-Einstein equations. We investigate the effects that this kind of dark matter imprints in the acoustic peaks of the cosmic microwave background. We find that the effect of the Bose-Einstein statistics is small, albeit perceptible, and is equivalent to an increase of non-relativistic matter. It is stressed that in this approach, the mass-to-temperature ratio necessary for ULBDM to be a plausible DM candidate is about five orders of magnitude. We show that reionization is also necessary and we address a range of consistent values for this model. We find that the temperature of ULBDM is below the critical value, impliying that Bose-Einstein condensation is inherent to the ULBDM paradigm.Comment: 6 pages, 5 figures, two authors added, improved, extended in section 2, more discussions to clarify some issues, references added, typos corrected, published version in Ap

Archivología, Bibliografía, Bibliotecología y Ciencia de la Información: representación terminológica en la producción profesional cubana 1905-2008

Presentation of a study linking the theoretical problems of the disciplines involved in the system of informative knowledge that found in the literature, —professional production—, in Cuba context, based on the analysis of categories of terms identifying information disciplines. It is based on a qualitative, historical and documentary research, and quantitative research from a temporary exhibition of Cuban professional production of Informative Literature 1905 to 2008, the results in both sections corroborate the status of Cuba informative phenomenon

Applied Analysis of Academic Studies on Webquests to the Teaching and Learning of a Second Language

Se trata de un estudio bibliométrico con el objetivo de mapear el uso de la Web Quest en la enseñanza y el aprendizaje de un segundo idioma. La revisión realizada se centra en la recopilación y descripción de las investigaciones académicas publicadas por las principales bases de datos científicas internacionales, siendo los puntos de interés por temas, procedimientos metodológicos y conclusiones; El estudio también sistematiza la contribución sobre la pertinencia de esta estrategia didáctica que se encuentra en los estudios descritos. Los resultados, en general, muestran que Web Quest son adecuados para la enseñanza basada en competencias y arrojan luz sobre innumerables ventajas de esta estrategia y la importancia de una mediación educativa eficaz.This is a bibliometric study with the aim of mapping the use of Web Quest in the teaching and learning of a Second Language. In the review, we deal with the compilation and description of academic researches published by the main international scientific databases, being the topics: themes, methodological procedures and conclusions; The study also systematizes the contribution on the relevance of this didactic strategy found in the described studies. Results, in general, show that Web Quest are suitable for the teaching based on competences and shed light on innumerable advantages of this strategy and the importance of an effective educational mediation

Opportunities from Metal Organic Frameworks to Develop Porous Carbons Catalysts Involved in Fine Chemical Synthesis

Funding Information: This work has been supported by Project ref. PID2021-126579OB-C32 from MCIN/AEI/10.13039/501100011033 and Project ref. UFV2023-38 from Universidad Francisco de Vitoria de Madrid. This work also received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. Maria Bernardo thanks FCT (Fundação para a Ciência e Tecnologia) for funding through program DL 57/2016—Norma transitória. Publisher Copyright: © 2023 by the authors.In the last decade, MOFs have been proposed as precursors of functional porous carbons with enhanced catalytic performances by comparison with other traditional carbonaceous catalysts. This area is rapidly growing mainly because of the great structural diversity of MOFs offering almost infinite possibilities. MOFs can be considered as ideal platforms to prepare porous carbons with highly dispersed metallic species or even single-metal atoms under strictly controlled thermal conditions. This review briefly summarizes synthetic strategies to prepare MOFs and MOF-derived porous carbons. The main focus relies on the application of the MOF-derived porous carbons to fine chemical synthesis. Among the most explored reactions, the oxidation and reduction reactions are highlighted, although some examples of coupling and multicomponent reactions are also presented. However, the application of this type of catalyst in the green synthesis of biologically active heterocyclic compounds through cascade reactions is still a challenge.publishersversionpublishe

MCDM/A in practice: methodological developments and real-world applications

Experts have long acknowledged that structuring complex decision problems well and considering multiple criteria explicitly in decision making lead to better, more informed decisions (Belton and Stewart, 2002). This field of research has seen important advances since the dawn of contemporary multiple-criteria decision aid studies in the early 1960s. MCDM and MCDA are now well-known acronyms for multiple-criteria decision making and multiple-criteria decision analysis, respectively. [...]info:eu-repo/semantics/publishedVersio

El derecho a la información en Cuba: consideraciones éticas y jurídicas en un entorno cambiante

Reflects on the right to information as a universal right and the right to liberty, emphasizing their representation in major international standards that recognize this right within the universe of human rights in the Americas. Comments on Freedom of Expression in a representation of constitutions of Latin America and Cuba, making a comparative study of Latin American and Cuban treatment constitutional context. Illustrate the definitions of right of information and access to information, concluding, from an ethical reflection of the new environment under the technological paradigm, with a review of the regulations in Cuba on access to the Internet and its influence on the right to information in Cuba.Se reflexiona acerca del derecho a la información como derecho universal y derecho de libertad, enfatizando su representación en las principales normativas internacionales que reconocen este derecho dentro del universo de derechos humanos en el continente Americano. Se comenta sobre libertad de expresión en el contexto constitucional latinoamericano y cubano, el tratamiento que tiene la libertad de expresión en una representación de cartas magnas de Latinoamérica y Cuba, haciendo un estudio comparativo de su tratamiento. Se distinguen las definiciones de derecho a la información y acceso a la información, concluyendo, a partir de una reflexión ética del nuevo entorno bajo el paradigma tecnológico, con una revisión de las normas legales en Cuba sobre el acceso a Internet y su influencia en el derecho a la información en Cuba

Terminología y disciplinas informativas: Reflexión interdisciplinar

Master en Bibliotecología y Ciencias de la Información. Investigadora agregada y profesora de postgrado de la Biblioteca Nacional José Martí. Profesora asistente adjunta de la Universidad de La Habana. Secretaria Profesional de la Revista Bibliotecas. Miembro del Consejo Asesor y de la Comisión de Postgrado de la Biblioteca Nacional. Miembro de la Unión de Historiadores de Cuba y secretaria de la Sección de Base de la BNJM

Del dicho al hecho: La primera Ley de Bibliotecas, de los Sistemas de Bibliotecas y de la Biblioteca Nacional de Cuba

An overview from the historical point of view through the legislation which has existed in Cuba relating to libraries, beginning from the first legal approaches that existed with intellectual property and those related to the Legal Depository. This explains the structure of the current Decree Law of Libraries, Library Systems and the National Library of Cuba, still in the process of approval, as the first and true advance towards a juridical regulation in our country of the work of such millenary institutionsSe realiza un recorrido desde el punto de vista histórico por las legislaciones que han existido en Cuba relacionadas con las bibliotecas, comenzando desde las primeras aproximaciones legales que existieron con la propiedad intelectual y las relacionadas con el Depósito Legal. Se expone la estructura del actual Decreto ley de Bibliotecas, de los Sistemas de Bibliotecas y de la Biblioteca Nacional de Cuba, en proceso aún de aprobación, como el primer y verdadero acercamiento hacia una regulación jurídica en nuestro país del trabajo de tan milenarias instituciones