278 research outputs found
Reply to "Comment on `Transition from Bose glass to a condensate of triplons in TlKCuCl'"
Showing low-temperature specific heat and other experimental data and also on
the basis of established physics, we argue against the comment made by Zheludev
and H\"{u}vonnen criticizing our recent study on the magnetic-field-induced
spin ordering and critical behavior in TlKCuCl, which is
described as the Bose glass-condensate transition of triplons.Comment: 2 pages, 2 figures, accepted for publication in Phys. Rev.
Effects of submergence on growth and survival of saplings of three wetland trees differing in adaptive mechanisms for flood tolerance
Aim of study: Withstanding total submergence and reaeration following submergence is essential for the survival and establishment of wetland species. We focused on “LOES–low oxygen escape syndrome” and “LOQS–low oxygen quiescence syndrome” and compared tolerances to total submergence among wetland woody species differing in morphological adaptation to soil flooding.Area of study, materials and methods: This study examined the survival of 2-year-old saplings of Taxodium distichum (LOQS species), and Alnus japonica and Metasequoia glyptostroboides, (LOES species), during and after total submergence. Saplings were completely submerged, then de-submerged to determine trends in survival and growth.Main results: The M. glyptostroboides and A. japonica saplings could not survive prolonged submergence for more than 8 weeks, whereas saplings of T. distichum survived for over 2 years. Submerged saplings of all species showed no significant growth or modifications in morphology and anatomy under water, such as shoot elongation, adventitious root formation, and/or aerenchyma development. All T. distichum saplings that were de-submerged in the second year had the same pattern of shoot growth regardless of differences in timing and seasonality of de-submergence. Wood formation in T. distichum saplings ceased during submergence and resumed after de-submergence in spring and summer, but not in autumn.Research highlights: T. distichum saplings, which survived longer submergence periods than A. japonica and M. glyptostroboides, had physiological characteristics, such as suspension of growth and metabolism, which allowed survival of protracted total submergence (at least 2 years) when saplings were immersed during the dormant stage before leaf flushing.Keywords: Alnus japonica; Metasequoia glyptostroboides; survival rates; Taxodium distichum; total submergence.Abbreviations: LOES, low oxygen escape syndrome; LOQS, low oxygen quiescence syndrome
An attempt to quantify Pedagogical Content Knowledge for Japanese high school physics teachers
A CASE STUDY OF HOW TO HANDLE THE ELECTRIC CURRENT CONCEPT
For quality science education, it is essential to fully grasp the concept of Pedagogical Content Knowledge (PCK) proposed by Shulman (1987). Therefore, there is a need to develop teachers' PCK in science education. In prior research, CoRes (Content Representations) and PaP-eRs (Pedagogical and Professional-experience Repertoires) (Magnusson et al., 1999) have been used as a framework to elicit from teachers the PCK components: orientations toward science teaching, knowledge of students’ understanding of science, knowledge of science curriculum, knowledge of instructional strategies, and knowledge of assessment in science. The CoRes consist of eight questions designed to elicit the science teacher's understanding of specific aspects of PCK, such as an overview of key ideas, points of confusion. The PaP-eRs is a useful framework for showing the deeper aspects of science teachers' PCK, for example, in this study it consists of CoRes-based interview transcripts. However, these studies represent teachers' PCK qualitatively and remain case studies. Therefore, the study we are presenting, aims to represent PCK quantitatively based on previous studies. The context of the investigation is how electric current is handled in the first hour of an electricity unit in high school.
METHOD
Beginning in May 2022, we preliminarily surveyed and analyzed four teachers who teach physics in high schools. Interviews were conducted with teachers based on the CoRes and PaP-eRs frameworks. Interview transcripts are categorized by PCK components. The number of utterances that appeared in each category was then recorded and represented as a radar chart.
RESULTS
An example of one teacher’s radar chart of the items with the highest number of utterances as 1 is shown in Figure 1 (see Abstract PDF). Each item represents knowledge of students’ understanding of science, knowledge of science curriculum, knowledge of instructional strategies, and knowledge of assessment in science. Since the first hour is assumed, the number of occurrences of knowledge of assessment in science may be low. It should be noted that this figure does not represent teacher qualifications, as the actual context and understanding of the students they teach in their learning varies among the teachers surveyed. In the current analysis, we only consider the number of utterances. Therefore, we would like to consider the need for weighting in future research. Although the number of surveys is limited at this time, we will increase the number of surveys and present a more detailed study.
REFERENCES
Magnusson, S. J., Borko, H., & Krajcik, J. S. (1999). Nature, sources, and development of pedagogical content knowledge for science teaching. In J. Gess-Newsome & N. Lederman (Eds.), Examining Pedagogical content Knowledge (pp. 95-132), Boston, MA: Kluwer Press.
Shulman, L. S. (1987). Knowledge and teaching: Foundations of the new reform. Harvard Educational Review, 57(1), 1–22
Magnetic field-induced one-magnon Raman scattering in the magnon Bose-Einstein condensation phase of TlCuCl
We report the observation of the -symmetric one-magnon Raman peak
in the magnon Bose-Einstein condensation phase of TlCuCl. Its Raman shift
traces the one-magnon energy at the magnetic point, and its intensity
is proportional to the squared transverse magnetization. The appearance of the
one-magnon Raman scattering originates from the exchange magnon Raman process
and reflects the change of the magnetic-state symmetry. Using the bond-operator
representation, we theoretically clarify the Raman selection rules, being
consistent with the experimental results.Comment: 6 pages, 4 figure
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