Search results for "Reflection"

Towards practical reflexivity in online discussion groups

2017

This paper continues the discussion about student-driven, interactive learning activities in higher education. Using object-oriented activity theory, the article explores the relational aspects of reflexive practice as demonstrated in five online discussions groups to develop students’ conceptual understanding. The purpose of the research is to describe both the process of reflection during online interaction and how practical engagement with the discipline is supported through pedagogical guidance. The students wrote short texts on the practice of health promotion ethics and discussed their perspectives in relation to theory and research. The analysis proved the importance of structural de…

Reflection and Refraction of Singularities for Wave Equations with Interface Conditions given by Fourier Integral Operators

1992

Cauchy problems for hyperbolic operators often have the property, that the singularities of the initial data propagate along the bicharacteristic strips of the operator (cf. e.g. [13]). We consider, in the linear case, the situation where the bicharacteristics hit transversally a spacelike interface, which is ‘active’ in the sense that the interface condition is given via certain Fourier integral operators. Taking the identity, we obtain classical transmission conditions. A suitable functional analytic setting is furnished by the interaction concept [3], [6], [7], which covers very general mutual influences of evolution phenomena on different domains.

Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea

2011

An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s-1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These observations coincided with high light levels detected by the telescope, interpreted …

Ultra-sensitive fluorescence spectroscopy of isolated surface-adsorbed molecules using an optical nanofiber.

2009

The strong radial confinement and the pronounced evanescent field of the guided light in optical nanofibers yield favorable conditions for ultra-sensitive surface spectroscopy of molecules deposited on the fiber. Using the guided mode of the nanofiber for both excitation and fluorescence collection, we present spectroscopic measurements on 3,4,9,10-perylenetetracarboxylic dianhydride molecules (PTCDA) at ambient conditions. Surface coverages as small as 1 per thousand of a compact monolayer still give rise to fluorescence spectra with a good signal to noise ratio. Moreover, we analyze and quantify the self-absorption effects due to reabsorption of the emitted fluorescence light by circumjac…

Analysis of multiple internal reflections in a parallel aligned liquid crystal on silicon SLM

2014

Multiple internal reflection effects on the optical modulation of a commercial reflective parallel-aligned liquid-crystal on silicon (PAL-LCoS) spatial light modulator (SLM) are analyzed. The display is illuminated with different wavelengths and different angles of incidence. Non-negligible Fabry-Perot (FP) effect is observed due to the sandwiched LC layer structure. A simplified physical model that quantitatively accounts for the observed phenomena is proposed. It is shown how the expected pure phase modulation response is substantially modified in the following aspects: 1) a coupled amplitude modulation, 2) a non-linear behavior of the phase modulation, 3) some amount of unmodulated light…

Multicommutation ATR-FTIR: determination of sodium alpha-olefin sulfonate in detergent formulations

2004

Abstract The mechanization of attenuated total reflectance measurements (ATR) in Fourier Transform Infrared spectrometry (FTIR) through the use of multicommutation has been evaluated in order to reduce the sample consumption and waste generation also avoiding risks of cells breaking. A new multicommutation ATR-FTIR procedure has been proposed for the determination of sodium alpha-olefin sulfonate (AOS) in liquid detergent formulations. The main advantages of this method are the low consumption of sample (96 ml per 100 determinations) and the analytical throughput (23 h −1 versus 15 h −1 for the manual mode). Results obtained for reference samples containing 7.52% to 9.52% (w/w) of AOS are i…

Negative work reflection, personal resources, and work engagement: the moderating role of perceived organizational support

2018

This day-level study examined the role of perceived organizational support (POS) in the context of employees’ negative work reflection during off-job time. We hypothesized that negative work reflec...

Fiber Bragg gratings with various chirp profiles made in etched tapers

1996

We have studied, both theoretically and experimentally, fibre Bragg gratings with a number of different chirp profiles. These chirp profiles can be easily achieved with a recently demonstrated technique involving a taper of desired profile being etched into the cladding of a fibre. Performances of gratings with linear, quadratic, periodically modulated and step chirp profiles are numerically analysed. The versatility of the technique is demonstrated when linearly and quadratically chirped gratings were made as examples of continuous chirp and gratings with step chirps were made as examples of discontinuously chirped structure.

Relict Paleo‐Asian Ocean subduction zones within the continental lithosphere: Insights from deep seismic reflection profiles

2019

Musical video clips on YouTube as a learning tool. Practical example in university teaching

2019

Se presenta una actividad docente en un entorno universitario mediante el análisis de conceptos de la Geografía Económica a través del visionado de videoclips musicales integrados en la plataforma YouTube. El alumnado (N=33) trabaja de manera grupal y colaborativamente, en sesiones presenciales y sesiones tutorizadas, seleccionando un grupo musical y una canción y analizando en profundidad la letra y las imágenes presentes en el vídeo, con el objeto de observar e intentar resolver problemáticas cotidianas. Son los propios estudiantes quienes califican la práctica. A través de un breve cuestionario los alumnos destacan la realización de un trabajo participativo, ameno, divertido y novedoso. …