1,034 research outputs found
Can explicit modeling of dynamical systems in physics change students’ beliefs concerning the nature of scientific knowledge?
Die Implementierung des Gemeinschaftsrechts in Österreich aus politik- und rechtswissenschaftlicher Sichtweise am Beispiel zweier ausgewählter EG- Richtlinien
Nicht angegebe
Kooperationszeiten in gebundenen Ganztagsklassen
Mit dem Rechtsanspruch auf Ganztagsbetreuung für Grundschulkinder ab dem Jahr 2026 ist ein weiterer Ausbau der Ganztagsbildung in Deutschland notwendig. Dabei darf der Blick auf die Qualität nicht in den Hintergrund rücken. Lehrkräftekooperation und multiprofessionelle Kooperation stellen Qualitätsmerkmale im Kontext Ganztagsschule dar. Gemeinsame Besprechungen zwischen Kooperierenden sind eine wichtige Gelingensbedingung dafür. Ob sich die Zeiten, die Klassenlehrkräfte mit Besprechungen im Rahmen der Lehrkräftekooperation verbringen, und die Zeiten, die sie mit Besprechungen im Rahmen der multiprofessionellen Kooperation verbringen, unterscheiden, wird im vorliegenden Beitrag untersucht. (DIPF/Orig.
A "synaptoplasmic cistern" mediates rapid inhibition of cochlear hair cells
Cochlear hair cells are inhibited by cholinergic efferent neurons. The acetylcholine (ACh) receptor of the hair cell is a ligand-gated cation channel through which calcium enters to activate potassium channels and hyperpolarize the cell. It has been proposed that calcium-induced calcium release (CICR) from a near-membrane postsynaptic store supplements this process. Here, we demonstrate expression of type I ryanodine receptors in outer hair cells in the apical turn of the rat cochlea. Consistent with this finding, ryanodine and other store-active compounds alter the amplitude of transient currents produced by synaptic release of ACh, as well as the response of the hair cell to exogenous ACh. Like the sarcoplasmic reticulum of muscle, the "synaptoplasmic" cistern of the hair cell efficiently couples synaptic input to CICR.Fil: Lioudyno, Maria. Johns Hopkins University School of Medicine; Estados UnidosFil: Hiel, Hakim. Johns Hopkins University School of Medicine; Estados UnidosFil: Kong, Jee-Hyun. Johns Hopkins University School of Medicine; Estados UnidosFil: Katz, Eleonora. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Waldman, Erik. Johns Hopkins University School of Medicine; Estados UnidosFil: Parameshwaran Iyer, Suchitra. Johns Hopkins University School of Medicine; Estados UnidosFil: Glowatzki, Elisabeth. Johns Hopkins University School of Medicine; Estados UnidosFil: Fuchs, Paul A.. Johns Hopkins University School of Medicine; Estados Unido
Die Erstellung von Erklärvideos als Prüfungsformat in der Wahrnehmung von Grundschullehramtsstudierenden
Als zentraler Bestandteil der universitären Ausbildung werden zahlreiche Erwartungen an den Einsatz von Prüfungen gestellt: Sie sollen Studierenden Rückmeldung zu ihren Lernprozessen geben und sie dazu motivieren, sich vertieft mit den Inhalten auseinanderzusetzen. Inwiefern alternative Prüfungsformate wie die Erstellung von Erklärvideos aus Sicht von Grundschullehramtsstudierenden solche Funktionen erfüllen, wird im Folgenden untersucht. (DIPF/Orig.
Evaluation of dried amorphous ferric hydroxide CFH-12® as agent for binding bioavailable phosphorus in lake sediments
Metal hydroxides formed from aluminum (Al) and iron (Fe) salts can be used as phosphorus (P) adsorbents in
lake restoration, but the application entails problems in low-alkaline lakes due to acid producing hydrolysis
and potential formation of toxic metal ions. Therefore, we tested the potential of applying CFH-12® (Kemira) –
a dried, amorphous Fe-oxide with no pH effect – in lake restoration. Since Fe3+ may become reduced in lake sed-
iments and release both Fe2+ and any associated P we also evaluated the redox sensitivity of CFH-12® in com-
parison with freshly formed Fe(OH)3. CFH-12® was added to undisturbed sediment cores from three Danish
lakes relative to the size of their mobile P pool (molar Fe:PMobile dose ratio of ~10:1), and P and Fe fluxes across
the sediment-water interface were compared with those from untreated cores and cores treated with freshly
formed Fe(OH)3. Under anoxic conditions, we found that CFH-12® significantly reduced the P efflux from the
sediments (by 43% in Lake Sønderby, 70% in Lake Hampen and 60% in Lake Hostrup) while the Fe 2+ efflux
remained unchanged relative to the untreated cores. Cores treated with freshly formed Fe(OH)3 retained more
P, but released significantly more Fe 2+
, indicating continued Fe3+ reduction. Finally, experiments with pure
phases showed that CFH-12® adsorbed less P than freshly formed Fe(OH)3 in the short term, but was capable
of adsorbing up to 70% of P adsorbed by Fe(OH)3 over 3 months. With product costs only 30% higher than Al
salts we find that CFH-12® has potential for use in restoration of low-alkaline lakes.The study was supported by Junta de Andalucía (project P10-RNM-
6630, Spain), MINECO CTM (project 2013-46951-R, Spain) and by the
European Regional Development Fund (ERDF). Funding was also ob-
tained from the Danish Centre for Lake Restoration (a Villum Centre of
Excellence).The study was supported by Junta de Andalucía (project P10-RNM-
6630, Spain), MINECO CTM (project 2013-46951-R, Spain) and by the
European Regional Development Fund (ERDF). Funding was also ob-
tained from the Danish Centre for Lake Restoration (a Villum Centre of
Excellence)
Distribution of mineral constituents in Yedoma permafrost: implications for Yedoma formation
Ice-rich permafrost deposits such as Yedoma are highly sensitive to thaw and given that they contain up to one third of the organic carbon content of the Northern circumpolar permafrost region, their degradation is considered to be a potential climate tipping point on Earth. Accurately predicting the impact of climate warming on the fate of organic carbon in Yedoma requires better constraints on the mineral element reserve in these deposits. This study provides evidence for the homogeneity of chemical composition and mineralogy of Yedoma deposits with depth. This suggests that upon deep thaw through thermokarst or thermo-erosion a high reserve in mineral nutrients is likely to be exposed also from deeper deposits
Theoriewissen und Unterrichtspraxis im Schulalltag. Erfahrungen aus der Lehrerfort- und -weiterbildung
Der folgende Beitrag berichtet über Erfahrungen aus 15 Jahren Lehrerfortbildung in den Bundesländern Nordrhein-Westfalen, Schleswig-Holstein und Hamburg. Dabei hat sich bestätigt, daß Interesse und Teilnahmebereitschaft vieler Lehrer an berufsspezifischer Fortbildung nicht nur auf Kurse beschränkt ist, in denen ausschließlich Rezepte für die Unterrichtspraxis der nächsten Wochen vermittelt werden, sondern sich ebenso auf Kurse richtet, in denen Lehrern durch die Auseinandersetzung mit Theorie die Möglichkeit gegeben wird, die eigenen Erfahrungen zu reflektieren. Auf Dauer akzeptiert wurden und werden Fortbildungsangebote, deren inhaltliche und methodische Realisation die Unterrichtserfahrungen der Lehrer ausdrücklich berücksichtigt, bei denen sie an Planung, Durchführung und Auswertung aktiv beteiligt werden, deren Theorieanteile nachvollziehbar der Analyse und Konstruktion eigenen Unterrichts dienen und bei denen sie Erfahrungen im Umgang mit neuen methodischen Ideen und Konzepten sammeln können. (DIPF/Orig.)The article describes experiences of 15 years of in-service teacher training in Northrhine-Westfalia, Schleswig-Holstein and Hamburg. It is pointed out that teachers are not only interested in courses which prepare for teaching the other day but that they are also interested in theory if this offers an opportunity to analyze their own practical experiences. It is important that teachers can participate in planning, realization and evaluation of courses and that theory is related to their practical problems and experiences
Narrativity in complex systems
Humans use narrative for making sense of their environment. In this chapter we ask if, and if so how and to what extent, our narrative mind can help us deal scientifically with complexity. In order to answer this question, and to show what this means for education, we discuss fundamental aspects of narrative understanding of dynamical systems by working on a concrete story. These aspects involve perception of complex systems, experientiality of narrative, decomposition of systems into mechanisms, perception of forces of nature in mechanisms, and the relation of story-worlds to modelling-worlds, particularly in so-called ephemeral mechanisms. In parallel to describing fundamental issues, we develop a practical heuristic strategy for dealing with complex systems in five steps. (1) Systems thinking: Identify phenomena and foreground a system associated with these phenomena. (2) Mechanisms: Find and describe mechanisms responsible for these phenomena. (3) Forces of nature: Learn to perceive forces of nature as agents acting in these mechanisms. (4) Story-worlds and models: Learn how to use stories of forces (of nature) to construct story-worlds; translate the story-worlds into dynamical-model-worlds. (5) Ephemeral mechanisms for one-time, shortlived, unpredictable, and historical (natural) events: Learn how to create and accept ephemeral story-worlds and models. Ephemeral mechanisms and ephemeral story-worlds are a means for dealing with unpredictability inherent in complex dynamical systems. We argue that unpredictability does not fundamentally deny storytelling, modelling, explanation, and understanding of natural complex systems
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