Search results for "Ford"
showing 10 items of 785 documents
Hexafluoro complex of rutherfordium in mixed HF/HNO3 solutions
2008
Formation of anionic fluoride-complexes of element 104, rutherfordium, produced in the 248 Cm( 18 O, 5n) 261 Rf reaction was studied by anion-exchange on an atom-at-a-time scale. It was found that the hexafluoro complex of Rf, [RfF 6 ] 2- , was formed in the studied fluoride ion concentrations of 0.0005-0.013 M. Formation of [RfF 6 ] 2- was significantly different from that of the homologues Zr and Hf, [ZrF 6 ] 2- and [HfF 6 ] 2- ; the evaluated formation constant of [RfF 6 ] 2- is at least one-order of magnitude smaller than those of [ZrF 6 ] 2- and [HfF 6 ] 2- .
Liquid-Phase Chemistry of Superheavy Elements
2013
An overview over the chemical separation and characterization experiments of the four transactinide elements so far studied in liquid phases, rutherfordium (Rf), dubnium (Db), seaborgium (Sg), and hassium (Hs), is presented. Results are discussed in view of the position of these elements in the Periodic Table and of their relation to theoretical predictions. Short introductions on experimental techniques in liquid-phase chemistry, specifically automated rapid chemical separation systems, are also given. Studies of nuclear properties of transactinide nuclei by chemical isolation will be mentioned. Some perspectives for further liquid-phase chemistry on heavier elements are briefly discussed.
Chemical studies on rutherfordium (Rf) at JAERI
2005
SummaryChemical studies on element 104, rutherfordium (Rf), at JAERI (Japan Atomic Energy Research Institute) are reviewed. The transactinide nuclide261Rf has been produced in the reaction248Cm(18O, 5n) at the JAERI tandem accelerator with the production cross section of about 13 nb. On-line anion-exchange experiments on Rf together with the lighter homologues, group-4 elements Zr and Hf, in acidic solutions have been conducted with a rapid ion-exchange separation apparatus. From the systematic study of the anion-exchange behavior of Rf, it has been found that the properties of Rf in HCl and HNO3solutions are quite similar to those of Zr and Hf, definitely confirming that Rf is a member of …
Fluoride complexation of rutherfordium (Rf, element 104)
2000
The fluoride complexation of the group-4 elements Zr, Hf and Rf, and of the pseudo-homolog Th, has been investigated in mixed HNO3/HF solutions by studying Kd values on both cation exchange resins (CIX) and anion exchange resins (AIX) using the automated rapid chemistry apparatus ARCA. On the CIX, the four elements are strongly retained as cations below 10-3M HF. For Zr and Hf, the decrease of the Kd values due to the formation of fluoride complexes occurs between 10-3M HF and 10-2M HF. For Rf and Th, this decrease is observed at one order of magnitude higher HF concentrations. On the AIX, for Zr and Hf, a rise of the Kd values due to the formation of anionic fluoride complexes is observed …
Approaches to teaching biology: A look at the contents
2020
En el marco de un diseño didáctico multirreferencial y contextualizado a necesidades específicas, tomar decisiones sobre los contenidos exige poner en juego conocimientos específicos de la didáctica de las ciencias. Tras relevar el uso del término enfoque en la bibliografía de didáctica de las ciencias experimentales y formación del profesorado, reconocemos como enfoques establecidos a CTSA, la interdisciplinariedad y la historia de las ciencias. Sin embargo, al conceptualizar nuestra postura acerca del concepto de enfoque, asociado a las decisiones que tomamos las y los docentes sobre los contenidos, realizamos un análisis epistemológico y didáctico de la Biología y de propuestas de enseña…
What color is your heart? The use of emojis in social activism processes
2020
En este artículo se analiza el empleo de los emojis como elemento de afiliación grupal en los procesos de activismo digital. A partir de la observación de diferentes perfiles activos en la red social Twitter y de tuits producidos por dichas cuentas, se identifica el uso de los emoji del corazón (en distintos colores) en concurrencia con diferentes hashtag como estrategias de encuadre. En este trabajo exploratorio, ilustramos nuestro estudio con la oposición que, entre el emoji del corazón verde y el emoji del corazón azul, se generó en Twitter, a partir de la remediación digital de los pañuelos de colores empleados por las y los activistas movilizados en torno a la discusión sobre la amplia…
Parenting Styles, Prosocial, and Aggressive Behavior: The Role of Emotions in Offender and Non-offender Adolescents
2017
The aim is to analyse the parenting styles effects (acceptance, negative control and negligence) on prosociality and aggressive behavior in adolescents through the mediator variables empathy and emotional instability, and also, if this model fits to the same extent when we study adolescents institutionalized due to problems with the law and adolescents from the general population, and at the same time, if the values of the different analyzed variables are similar in both groups of adolescents. We carried out a cross-sectional study. 220 participants from schools in the metropolitan area of Valencia took part in the study. Also, 220 young offenders took part recruited from four Youth Detenti…
Pathway network inference from gene expression data
2014
[EN] Background: The development of high-throughput omics technologies enabled genome-wide measurements of the activity of cellular elements and provides the analytical resources for the progress of the Systems Biology discipline. Analysis and interpretation of gene expression data has evolved from the gene to the pathway and interaction level, i.e. from the detection of differentially expressed genes, to the establishment of gene interaction networks and the identification of enriched functional categories. Still, the understanding of biological systems requires a further level of analysis that addresses the characterization of the interaction between functional modules. Results: We presen…
Digital Games in Early Childhood: Broadening Definitions of Learning, Literacy, and Play
2017
Digital games attract children and young people with imaginary worlds, fascinating stories, and shared experiences with peers. They also can add children’s learning and motivation and offer a variety of new affordances to explore and play with. The pedagogical use of digital games has been found to potentially intensify a more critical use and understanding of varied forms of media. In this chapter, we will focus on analyzing the role of digital games in early childhood, especially from the perspectives of learning, literacy, and play. This chapter examines digital games as playing an essential role in young children’s overall technology experiences, particularly in the context of the socia…
Comprehensive database on Induan (Lower Triassic) to Sinemurian (Lower Jurassic) marine bivalve genera and their paleobiogeographic record
2014
Marine bivalve genera that were described or mentioned for Triassic and Lower Jurassic deposits worldwide are reviewed in terms of their validity, stratigraphic range, paleogeographic distribution, paleoautoecology and shell mineralogy. Data were originally compiled at species level and are arranged systematically. A brief discussion for each genus includes synonymy, taxonomic status and included subgenera, as well as current uncertainties about their validity and range. The distribution of each genus is also shown on paleogeographic maps. Type species and first and last appearances of each genus are also mentioned. We recognize as valid 280 genera and their included subgenera, and we furth…