Single crystal growth and study of the magnetic properties of the mixed spin-dimer system Ba3−x_{3-x}Srx_{x}Cr2_{2}O8_{8}

The compounds Sr$_{3}$Cr$_{2}$O$_{8}$ and Ba$_{3}$Cr$_{2}$O$_{8}$ are insulating dimerized antiferromagnets with Cr$^{5+}$ magnetic ions. These spin-$\frac{1}{2}$ ions form hexagonal bilayers with a strong intradimer antiferromagnetic interaction, that leads to a singlet ground state and gapped triplet states. We report on the effect on the magnetic properties of Sr$_{3}$Cr$_{2}$O$_{8}$ by introducing chemical disorder upon replacing Sr by Ba. Two single crystals of Ba$_{3-x}$Sr$_{x}$Cr$_{2}$O$_{8}$ with $x=2.9$ (3.33\% of $mixing$) and $x=2.8$ (6.66\%) were grown in a four-mirror type optical floating-zone furnace. The magnetic properties on these compounds were studied by magnetization measurements. Inelastic neutron scattering measurements on Ba$_{0.1}$Sr$_{2.9}$Cr$_{2}$O$_{8}$ were performed in order to determine the interaction constants and the spin gap for $x=2.9$. The intradimer interaction constant is found to be $J_0$=5.332(2) meV, about 4\% smaller than that of pure Sr$_{3}$Cr$_{2}$O$_{8}$, while the interdimer exchange interaction $J_e$ is smaller by 6.9\%. These results indicate a noticeable change in the magnetic properties by a random substitution effect

The drivers of digital investment broker adoption

Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceConsumers around the world are more active in financial markets and have taken greater responsibility for their financial well-being, increasingly adopting digital investment brokers to perform their financial investments. Also, there has been increased competition in financial markets over the years, with more players in the investment landscape. In order to understand the factors that lead to the adoption of a digital investment broker, which is the main goal of the research, a model adapted from Technology Acceptance Model (TAM) and Unified Theory of Acceptance and Use of Technology (UTAUT) was developed. An initial sample of 279 Brazilians was obtained, of which 126 are adopters of digital investment brokers. From this sample, the model was tested and among the conclusions of the research it is highlighted that perceived usefulness, data visualization and subject norm have a significant positive impact on behavioral intention of digital investment broker adoption. Also, the perceived ease of use positively but indirectly influences, through the data visualization, the intention of digital investment broker adoption. Finally, as there is still a lack of research on the adoption of digital investment brokers, it was recommended that new studies be carried out in different countries, and that new studies include different variables in the research model, in order to obtain a better understanding of the individual investor behavior in the adoption of digital investment brokers

Liver involvement in pediatric celiac disease

Celiac disease (CD) is an intestinal inflammatory disease that manifests in genetically susceptible individuals when exposed to dietary gluten. It is a common chronic disorder, with a prevalence of 1% in Europe and North America. Although the disease primarily affects the gut, the clinical spectrum of CD is remarkably varied, and the disease can affect many extraintestinal organs and systems, including the liver. The hepatic dysfunction presenting in CD ranges from asymptomatic liver enzyme elevations or nonspecific reactive hepatitis (cryptogenic liver disorders), to chronic liver disease. In this article, we review the clinical presentations and possible mechanisms of CD-related liver injury to identify strategies for the diagnosis and treatment of these disorders in childhood

Community Segmentation and Inclusive Social Media Listening

Social media analytics provide a generalized picture of situational awareness from the conversations happening among communities present in social media channels that are that are, or risk being affected by crises. The generalized nature of results from these analytics leaves underrepresented communities in the background. When considering social media analytics, concerns, sentiment, and needs are perceived as homogenous. However, offline, the community is diverse, often segmented by age group, occupation, or language, to name a few. Through our analysis of interviews from professionals using social media as a source of information in public service organizations, we argue that practitioners might not be perceiving this segmentation from the social media conversation. In addition, practitioners who are aware of this limitation, agree that there is room for improvement and resort to alternative mechanisms to understand, reach, and provide services to these communities in need. Thus, we analyze current perceptions and activities around segmentation and provide suggestions that could inform the design of social media analytics tools that support inclusive public services for all, including persons with disabilities and from other disadvantaged groups.publishedVersionPaid open acces

Conceptual Modeling: the Linguistic Approach

After more than thirty years of its first introduction, conceptual modeling remains an important research field, which has been recently addressed by the literature on semantic interoperability in its various forms (model integration, service interoperability, knowledge harmonization, taxonomy alignment), domain engineering and the creation of conceptual models through Natural Language Processing (NLP), to name a few. In the database conceptual design, the designer must learn the language used in the Universe of Discourse (UoD) to be modeled, along with its underlying concepts, and then represent such concepts in a modeling language. Thus, the conceptual modeling process can be seen as a translation. For the resulting model to be both detailed and unambiguous, the designer must represent the UoD in a generative language which constructs can convey the same concepts represented in the respective natural language. For the whole process to be effective, we argue that the adoption of modeling languages and methodologies that are based on well-founded ontological theories is required. We propose the use of a linguistic approach for conceptual modeling from natural language texts, and illustrate how it may be applied using the well-founded modeling language OntoUML

Bibliometric analysis of publications related to the pharmaceutical supply chain before and after the Covid-19 pandemic in the period 2010-2021

The pharmaceutical industry has undergone changes in the management of its logistics processes, making it vulnerable to disruptions such as the Covid-19 pandemic. This study compares the scientific production on the pharmaceutical chain during the period 2010-2021, divided into two periods, through a bibliometric review of research indexed in Scopus and Web of Science. The main authors, institutions, countries, journals and thematic areas are identified, and the studies of greatest scientific relevance are analyzed. The VosViewer tool is used to visualize the relationships between authors and between keywords. A total of 785 publications related to the pharmaceutical chain were identified during 2010-2021. The institutions with the highest publication activity were concentrated in Iran, Morocco and Saudi Arabia. Co-authorship and keyword co-occurrence analyses show the main authors and research topics in both periods. Research on the pharmaceutical chain has been increasing in recent years, but few relate to COVID-19

El Programa de las 900 escuelas y el impacto real de las escuelas criticas en la Provincia de Talca

90 p

Concepciones y creencias docentes sobre el colegio democrático

El proceso de construcción de la democracia en el colegio tiene como actor principal al docente, cuyas concepciones y creencias influirán en su práctica pedagógica. Por este motivo, el presente estudio tuvo como propósito explorar las concepciones y creencias de los docentes sobre el colegio democrático. Se entrevistó a ocho profesores de una institución educativa pública secundaria. Los resultados mostraron que ellos no reconocen la construcción de una sociedad democrática como fin de la educación, sino que perciben que su objetivo principalmente es formar emprendedores y personas preparadas para el mundo laboral. Si bien mencionan el desarrollo de habilidades y la formación integral como fines de la educación, estos no se dirigen al desarrollo de la ciudadanía de sus estudiantes. La mayoría comprende la democracia principalmente como un sistema de gobierno, algunos solamente como una forma de vida y otros mencionan ambas. Además, piensan que esta es blanda, no sabe aplicar normas, que en democracia la libertad de expresión se tergiversa y que los políticos se aprovechan de la ignorancia del pueblo para conseguir votos. En el colegio la democracia se entiende principalmente como participación en programas escolares para la democracia o en acciones centradas en el docente. Los profesores consideran que las familias no contribuyen con la formación de los estudiantes, que el colegio no puede hacer nada por los estudiantes con familias problemáticas y que los alumnos llegan con muchas limitaciones que dificultan la enseñanza y el aprendizaje. Además, sus creencias sobre su rol como docentes los distancian de posturas democráticas. Sobre disciplina y métodos correctivos se encuentra poca claridad y frustración en los profesores. La mayoría está de acuerdo con la participación de alumnos en la elaboración de normas, pero con límites y guía del docente.Teachers are principal actors in the process of building democracy in school, while their conceptions and beliefs have influence in their pedagogical practice. Therefore, the aim of the present study was to explore teacher’s conceptions and beliefs about democratic schools. Eight public secondary school teachers where interviewed for the study. Results show that teachers do not recognize that building a democratic society is one of the aims of education. Instead, they perceive entrepreneurship and educating for the work world as its principal aims. Even though they mention development of abilities and integral training, these are not directed to the development of citizenship in their students. The majority of teachers understand democracy only as a government system, others just as a way of living and some mention of these characteristics. Also, they think that democracy is weak, do not apply rules, in democracy freedom of expression is misunderstood and politicians take advantage of peoples ignorance to get votes. In school, democracy is understood principally as involvement in school programs for democracy or teacher centered actions. Teachers consider families can’t contribute to student’s education, school can’t do anything for students with problematic families and that they arrive to school with several limitations that make difficult teaching and learning. Additionally, they hold beliefs about teacher’s role that distance them from democratic stances. Little clarity and frustration was found in relation to discipline and corrective methods. The majority of teachers agree with student’s participation in the creation of rules, but with limits and teacher’s guide.Tesi

Signals of Transition in Crisis Management: Insights from a Study of Social Media Use in Public Service Organizations

In crisis informatics, little attention is placed on how transitions occur between periods of crisis and non-crisis. The analysis of transition behaviors in organizations could respond to both the cyclicality of risk and crisis management, and the need for continuity of services provided to the community. In studying transitions, we focus on social media use as a support system. Thus, with the objective to gain an insight into how sociotechnical systems navigate through periods of crisis and non-crisis, we leverage individual experiences that rely on social media as a source of information in public service organizations and developers of social media analytics support tools. The main contribution of this study is the explanation and conceptualization on how transitions happen by framing social media as a support system of information for crisis management. In addition, we highlight the return to a new steady-state, an overlooked area of organizational transitions and continuity

METODOLOGÍA PARA LA ENSEÑANAZA LA PLANEACIÓN DE LA AUDITORÍA DE ESTADOS FINANCIEROS A ESTUDIANTES DE CIENCIAS ADMINISTRATIVAS

El presente artículo aborda una temática de gran significación. En este sentido, la planeación de la auditoría de estados financieros garantiza su realización con plena calidad al posibilitar los riesgos y determinar con adecuación y razonabilidad los procedimientos de auditoría que correspondan aplicar por el auditor actuante. Para ello, en el artículo se expone una valoración científica en torno a las concepciones teóricas y prácticas relacionadas con el proceso de planeación de la auditoría de estados financieros. Asimismo, se sistematizan las precisiones contenidas al respecto en las Normas Internacionales de Auditoría y se ofrecen consideraciones generales para desarrollar este importante proceso por parte de los auditores. Por tanto, se realiza una valoración acerca de temáticas específicas como: la estrategia global de auditoría y plan de auditoría, el conocimiento de la organización a auditar, la planificación operacional de la auditoría de estados financieros, y la mejora continua al plan de la auditoría de estados financieros