428 research outputs found
Work Group 3 Position Paper: Teacher Education and Teaching/Learning Quantum Physics
In this article the discussion of Working Group 3 during the GIREP online seminar 2020 on teaching and learning quantum physics in teacher education is summarized. Conclusions are drawn and research desiderata formulated
Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite
The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopy–electron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research
The role of mathematics for physics teaching and understanding
That mathematics is the “language of physics” implies that both areas are deeply interconnected, such that often no separation between “pure” mathematics and “pure” physics is possible. To clarify their interplay a technical and a
structural role of mathematics can be distinguished. A thorough understanding of this twofold role in physics is also important for shaping physics education especially
with respect to teaching the nature of physics. Herewith the teachers and their pedagogical content knowledge play an important role. Therefore we develop a model of PCK concerning the interplay of mathematics and physics in order to provide a theoretical framework for the views and teaching strategies of teachers. In an exploratory study four teachers from Germany and four teachers from Israel have been interviewed concerning their views and its transfer to teaching physics. Here we describe the results from Germany. Besides general views and knowledge held by all or nearly all teachers we also observe specific individual focus depending on the teachers’ background and experiences. The results fit well into the derived model of PCK
Fattori che ispirano studenti delle scuole superiori di 14 nazioni europee allo studio della fisica
Nell'ambito del progetto Europeo Hope, che ha coinvolto 72 partner Europei, \ue8 stata svolta un'indagine sui fattori che ispirano studenti di scuola superiore interessati alla fisica a scegliere una laurea in fisica. \uc8 stato somministrato un questionario con domande aperte e con valutazione su scala a 5 livelli. L'indagine ha riguardato 1475 studenti di 14 nazioni partecipanti a specifici eventi (olimpiadi, scuole estive, laboratori). Metodi diversi di analisi evidenziano che la scelta di una laurea in fisica \ue8 spesso esito di un interesse precoce sostenuto nel corso degli anni
Development of a device to simulate tooth mobility
Objectives: The testing of new materials under simulation of oral conditions is essential in medicine. For simulation of fracture strength different simulation devices are used for test set-up. The results of these in vitro tests differ because there is no standardization of tooth mobility in simulation devices. The aim of this study is to develop a simulation device that depicts the tooth mobility curve as accurately as possible and creates reproducible and scalable mobility curves. Materials and methods: With the aid of published literature and with the help of dentists, average forms of tooth classes were generated. Based on these tooth data, different abutment tooth shapes and different simulation devices were designed with a CAD system and were generated with a Rapid Prototyping system. Then, for all simulation devices the displacement curves were created with a universal testing machine and compared with the tooth mobility curve. With this new information, an improved adapted simulation device was constructed. Results: A simulations device that is able to simulate the mobility curve of natural teeth with high accuracy and where mobility is reproducible and scalable was developed
The Randomized Shortened Dental Arch Study: Tooth Loss
The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant
Quantum Theory contents insertion in High School curricula
A inovação científica e tecnológica do século XX foi esmagadora. Contudo, a nossa experiência docente permite-nos afirmar que as aprendizagens na escola secundária estão longe de acompanhar a evolução que se verifica na sociedade atual. No entanto, já estão a ser incluídos alguns conteúdos de Física Moderna nos currículos oficiais de vários países, parecendo evidenciar uma preocupação em atualizar a preparação dos jovens para o mundo que os rodeia. Neste artigo relatamos um estudo que fizemos acerca dos currículos de Física de alguns países, sobretudo no que diz respeito à Teoria Quântica, a grande invenção do século XX, tentando identificar os conteúdos selecionados e a maneira como estes se integram nas orientações curriculares gerais.In the XXth century, scientific and technological innovation has been overwhelming. Our teaching
profession lead us to believe that studies in High Schools do not follow the evolution of ideas that characterizes
our modern society. However, some contents of Modern Physics are already included in the official curricula
of several countries, which seem to be worried about the improvement of today’s youth training. In this paper
we report a study made about Physics’ curricula in several countries, emphasizing Quantum Theory issues, the
biggest invention of the XXth century, trying to identify the selected subjects selected and the way they fit into
general curricula orientations
ВЛИЯНИЕ ТРАДИЦИОННОГО ИЛИ ШОКОВОГО ЗАМОРАЖИВАНИЯ НА ПОТЕРИ ПРИ РАЗМОРАЖИВАНИИ И СТРУКТУРНО-МЕХАНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ГОВЯДИНЫ
Abstract The effect of conventional and shock freezing on thaw drip loss and firmness of beef meat was studied. The meat samples was frozen in conventional freezer at -18 °C and shock frozen meat samples reached -50 °C temperature. Drip loss was measured by weighing the meat sample during thawing. The firmness was performed with TA-XT Plus Texture Analyzer with the volodkevich bite jaws. The firmness score and thaw drip loss differences did not been recognized between conventional and shock freezing meat excluding 7th day.АннотацияИзучали влияние традиционного и шокового замораживания на потери сока при размораживании и жёсткость говядины. Образцы мяса были заморожены в традиционном морозильном аппарате при -18 °C, в то время как температура образцов мяса, подвергнутых шоковому замораживанию, достигала -50 °C. Потери вследствие вытекания сока измеряли путём взвешивания образца мяса во время размораживания. Определение жёсткости проводили на анализаторе текстуры TA-XT Plus Texture Analyzer с устройством Володкевича для тестирования силы резания. Не было установлено различий в жёсткости и потерях вследствие вытекания сока при размораживании между традиционным и шоковым замораживанием, за исключением седьмого дня
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