Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.     

The Use of Different Translation Devices to Analyze Knowledge-Building in a University Chemistry Classroom

Research in Science Education - This research draws on Legitimation Code Theory (LCT) to understand the epistemic dimension of the higher education classroom discourse of a professor who is well...     

Risk Society and Science Education

Science & Education - The current COVID-19 pandemic raises reflection on the new roles of science education in citizen education in a world characterized by civilization risks, derived from the...     

Lifelong learning policies supporting young adults in two Portuguese regions

ABSTRACT

Precarious jobs and unemployment have become common issues for many young adults due to the unfavourable labour market situation in Portugal. Against this background, lifelong learning (LLL) policies have been called in to play a role in creating economic growth and supporting the social inclusion of young adults in vulnerable educational and economic circumstances. These policies are defined at the national level; however, their implementation depends on the action of local actors who face specific challenges. This paper explores disparities in the definition and implementation of LLL policies targeting young adults in two Portuguese regions. Specifically, we analyse professional courses in Vale do Ave (North) and adult education and training courses in Alentejo Litoral (South). These regions were selected due to their dissimilar economic structure. This study adopted a qualitative approach through interviews with LLL experts and policy roundtables with local stakeholders and decision-makers in both regions. Data were transcribed and analysed using NVivo 10. The study shows that the two regions have different cooperation networks between local stakeholders, and that these impact the opportunities to influence the regional skills formation system differently. Also, the study shows that LLL policies are not designed to address destandardised life courses.     

A Remote Sensing Class Exercise to Study the Effects of El Niño in South America

Satellite remote sensing techniques can be used for conducting environmental change detection studies following a natural disaster. Modern computer technology and free access to global satellite imagery allows educators to introduce undergraduate students to the fields of remote sensing and encourage their scientific participation through a research assignment that also serves as an educational exercise. The undergraduate physical science laboratory manuals used in higher education that contain printed remote sensing material often fail to effectively achieve these goals. This class exercise utilizes digital satellite imagery for studying the floods that resulted in the Paraná River region in South America during El Niño 1997–98. In addition, it examines vegetation cover and spectral profiles from the study area in order to further understand and assess the changes that were caused by this recurrent climatic anomaly.     

Teamwork and Entrepreneurial Behavior among K-12 Teachers in the United States

Abstract

This study attempted to identify the predictors of entrepreneurial behavior by assessing a series of variables that included teamwork skills and demographic variables, and to explore teachers’ experiences with teamwork. A sample of 367?K-12 public school teachers completed the survey. The findings indicated that teamwork predicts entrepreneurial behavior. Most participants received teamwork training through their school districts. Barriers to teamwork included time constraints, individual differences, and inability to collaborate.     

Teaching strategies to create visual representations of key ideas in content area text materials: A longterm intervention inserted in school curriculum

This paper describes a long-term research in which middle-grade school children were taught how to represent visually text key ideas through idea-mapping techniques. It consists of three studies, one for each year of our research. Children were at sixth grade when the instruction began, and they were at eighth grade when it finished. Another group of children from a different public school served as control group. Instruction was very close to the real school conditions: instructors were ordinary teachers, instruction was inserted in the content area curriculum, and ordinary textbooks were regularly employed, though combined with specially elaborated materials. Results were positive in the case of the first and third year, depending on instructional conditions. Positive effects were found on recall, comprehension and learning, but they were different in the three studies. Theoretical and practical implications are discussed.     

La educación de los sentidos en la Argentina de Perón. El caso de la revista Noticioso y la cinematografía escolar

RESUMEN

En la Argentina de mediados del siglo XX comenzó con un fuerte sesgo estatal a pensarse en la cinematografía escolar como un eficaz método pedagógico de difusión de un pretendido ideario simultáneamente emancipador y propagandístico. Del mismo modo que otros gobiernos de diversas filiaciones ideológicas, la presidencia de Juan Domingo Perón estuvo signadas por una política de la imagen que se enfocó en educar los sentidos de las futuras generaciones de argentinos. En este caso se muestra una política en particular, como lo fue la revista Noticioso entre 1952 y 1955, cuyo análisis refleja el exponencial crecimiento del rol estatal, hasta ocupar un lugar central no sólo en la reproducción de cine educativo, sino también de la filmación, distribución y proyección de los celuloides. En síntesis, con la creación en 1948 del Departamento de Radioenseñanza y Cinematografía Escolar como organismo específicamente dedicado a la enseñanza audiovisual, y especialmente con la publicación de Noticioso, puede verse un síntoma de las políticas gubernamentales que el peronismo forjó para la formación de nuevos ciudadanos, en el marco de la pretendida Nueva Argentina.