545 research outputs found
Participant-oriented planning and evaluation of in-service teacher training
Voraussetzung erfolgreicher Lernorganisation für lernende Lehrer sind nicht nur Inhalte und Methoden, sondern Mitbeteiligung und Akzeptanz durch die Teilnehmer. Aus Fortbildungserfahrungen mit Lehrern werden Formen beschrieben, die adressatenbezogene Planung und Erfolgsorientierung ermöglichen. Vor allem wird Wert gelegt auf Erhebungs- und Beobachtungsmethoden, die 1. in den Kurs integriert sind oder interne Rückspiegelungen zulassen und deshalb weder als funktional erfahren werden noch die begrenzte Zeit inhaltsleer beanspruchen, 2. Hilfsmittel für die Orientierung im Lernprozeß bereitstellen, 3. Selbsteinschätzung und Kurswahrnehmung der Teilnehmer verdeutlichen, um Wahrnehmungen der Kursleitung zu korrigieren. Im Mittelpunkt steht die These, daß nicht nur der einzelne Kurs Nutzen aus Erhebungen zieht, sondern jede zielgruppenorientierte Planung: Die Erhebung wirkt über den Augenblick, für den sie gemacht ist, hinaus. Dabei wird für die Vorausplanung nicht nur die Typik der Lehrerrolle herangezogen, sondern auch die Erfahrung: Lehrer wissen, was Lehrer brauchen. (DIPF/Orig.)Since teachers themselves know best what teachers need, the author arguments for a planning and evaluating of teacher training courses which allow for a better adaptation of courses to teachers. Most important are methods of Observation and feedback which are 1. integrated elements of the training, 2. useful means for modifying the learning process within the course, and 3. helpful to illustrate the perception of the course and the results by the participants
Effect of Confinement on Capillary Phase Transition in Granular Aggregates
Using a 3D mean-field lattice-gas model, we analyze the effect of confinement on the nature of capillary phase transition in granular aggregates with varying disorder and their inverse porous structures obtained by interchanging particles and pores. Surprisingly, the confinement effects are found to be much less pronounced in granular aggregates as opposed to porous structures. We show that this discrepancy can be understood in terms of the surface-surface correlation length with a connected path through the fluid domain, suggesting that this length captures the true degree of confinement. We also find that the liquid-gas phase transition in these porous materials is of second order nature near capillary critical temperature, which is shown to represent a true critical temperature, i.e., independent of the degree of disorder and the nature of the solid matrix, discrete or continuous. The critical exponents estimated here from finite-size scaling analysis suggest that this transition belongs to the 3D random field Ising model universality class as hypothesized by F. Brochard and P.G. de Gennes, with the underlying random fields induced by local disorder in fluid-solid interactions
The Effect of Confinement on Capillary Phase Transition In Granular Aggregates
Utilizing a 3D mean-field lattice-gas model, we analyze the effect of
confinement on the nature of capillary phase transition in granular aggregates
with varying disorder and their inverse porous structures obtained by
interchanging particles and pores. Surprisingly, the confinement effects are
found to be much less pronounced in granular aggregates as opposed to porous
structures. We show that this discrepancy can be understood in terms of the
surface-surface correlation length with a connected path through the fluid
domain, suggesting that this length captures the true degree of confinement. We
also find that the liquid-gas phase transition in these porous materials is of
second order nature near capillary critical temperature, which is shown to
represent a true critical temperature, i.e. independent of the degree of
disorder and the nature of solid matrix, discrete or continuous. The critical
exponents estimated here from finite-size scaling analysis suggest that this
transition belongs to the 3D random field Ising model universality class as
hypothesized by P.G. de Gennes, with the underlying random fields induced by
local disorder in fluid-solid interactions
Структура, механические свойства и особенности поведения при деформации пористой керамики на основе диоксида циркония
Пористая керамика находит широкое применение в качестве огнеупорного материала, фильтров и материалов медицинского назначения в качестве остеозамещающих элементов (эндопротезов).
В полученном материале, с развитой поровой структурой, под нагрузкой происходит мартенситное превращение из тетрагональной в моноклинную фазу. Это должно способствовать повышению вязкости разрушения, а также надежности и долговечности пористой керамики, в условиях, например, мало- и многоцикловой усталости.The porous ceramics finds broad application as a refractory material, filters and medical materials as osteosubstaining elements (endoprostheses).
In the received material, with the developed porous structure, under loading there is a martensitic transformation from tetragonal into a monoclinic phase. It has to promote increase in fracture toughness and also reliability and durability of porous ceramics, under conditions such as low and multi-cycle fatigue
Epidemiology of mid-buccal gingival recessions according to the 2018 Classification System in South America: Results from two population-based studies
AIM
The aim of this investigation was to estimate the prevalence, severity and extent of mid-buccal gingival recessions (GRs; classified according to the 2018 Classification System) and to identify their risk indicators in the South American population.
MATERIALS AND METHODS
Epidemiological data from two cross-sectional studies-performed on 1070 South American adolescents and 1456 Chilean adults-were obtained. All participants received a full-mouth periodontal examination by calibrated examiners. GR prevalence was defined as the presence of at least one mid-buccal GR ≥ 1 mm. GRs were also categorized into different recession types (RTs) according to the 2018 World Workshop Classification System. Analyses for RT risk indicators were also performed. All analyses were carried out at the participant level.
RESULTS
The prevalence of mid-buccal GRs was 14.1% in South American adolescents and 90.9% in Chilean adults. In South American adolescents, the prevalence of RTs was 4.3% for RT1 GRs, 10.7% for RT2 GRs and 1.7% for RT3 GRs. In Chilean adults, the prevalence of RT1 GRs was 0.3%, while the prevalence of RT2 and RT3 GRs was 85.8% and 77.4%, respectively. Full-Mouth Bleeding Score (FMBS; <25%) was associated with the presence of RT1 GRs in adolescents. The risk indicators for RT2/RT3 GRs mainly overlapped with those for periodontitis.
CONCLUSIONS
Mid-buccal GRs affected 14.1% of South American adolescents, whereas they affected most of the Chilean adult population (>90%). While RT1 GRs are more commonly observed in a non-representative cohort of South American adolescents (when compared to Chilean adults), the majority of Chilean adults exhibit RT2/RT3 GRs
Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves
We study parametric resonance of interacting waves having the same wave
vector and frequency. In addition to the well-known period-doubling instability
we show that under certain conditions the instability is caused by a Hopf
bifurcation leading to quasiperiodic traveling waves. It occurs, for example,
if the group velocities of both waves have different signs and the damping is
weak. The dynamics above the threshold is briefly discussed. Examples
concerning ferromagnetic spin waves and surface waves of ferro fluids are
discussed.Comment: Appears in Phys. Rev. Lett., RevTeX file and three postscript
figures. Packaged using the 'uufiles' utility, 33 k
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