Lesson study in teacher development: A paradigm shift from a culture of receiving to a culture of acting and reflecting

This article describes how lesson study creates a process of teacher learning whilst developing student learning through collaborative planning, guided observation and reflection. It presents a framework for conducting lesson study in a teacher development programme in Lower Austria. The role of knowledgeable others in the development of ownership for educational change towards competence‐oriented teaching and learning is explored and an overview of the organisational requirements and practical effects in the implementation of professional learning communities is given. In doing so, the article sheds light on training strategies and material development. Thus, insights on a paradigm shift in teacher development towards learning focused on discourse and reflected action are presented.     

Embedded Stem Priming Effects in Prefixed and Suffixed Pseudowords

Previous research has repeatedly revealed evidence for morpho-orthographic priming effects in suffixed words. However, evidence for the morphological chunking of prefixed words is sparse and ambiguous. The goal of the present study was to directly contrast the processing of prefixed and suffixed pseudowords within the same experiment. We carried out a masked primed lexical decision experiment, in which the same target (AMOUR [LOVE]) was preceded by a prefixed (préamour [prelove]), a nonprefixed (brosamour [broslove]), a suffixed (amouresse [lovedom]), and a nonsuffixed (amourugne [lovedel]) prime. The results revealed significant priming across all four conditions. Moreover, priming was modulated by individual differences in reading proficiency. High-proficiency readers showed evidence for embedded stem priming effects, independent of whether stems occurred in combination with a real affix or a nonaffix. This finding is of relevance to recent morphological processing theories, suggesting that embedded stems represent salient activation units during the reading of complex pseudowords.     

Conceptions of intelligence and learning and perceptions of self-efficacy among students at the end of primary school

Several studies have focused on the role of students’ conceptions of intellectual ability, the learning process and the self-efficacy. However, these three parameters have not been integrated and analysed within the same model. Against this background, the objective of our research is to identify the links that develop between these three constructs. To this end, we have put forward two hypotheses: 1. The conception that intelligence is constructed directly and positively affects the conception that learning is a constructive process. This has a positive impact on perceived self-efficacy. 2. The conception that intelligence is a fixed trait directly and positively affects the conception that learning is a reproductive process and leads to lower perceptions of self-efficacy. To test these hypotheses, we conducted research using a questionnaire distributed among 1112 students in their last year of primary school. The questionnaires were subject to statistical analysis using structural equation modelling. The results confirm our hypotheses and thus show the relevance of our model.     

Working while studying: the impact of term-time employment on dropout rates

There are many possible reasons why students leave university prior to degree completion, and one of the more commonly cited is being employed while studying. This paper analyses the impact of employment status on dropout rates using survival analysis. It finds that employment status does have an impact on dropout rates; students who work full time alongside studying full time are less likely to complete their programme than students working short part-time or not working at all. However, it seems as if there is a threshold to how much students can work, as working more than 20?h a week (long part-time work) increase the risk of dropout as much as full-time work. Integrating employment status into the analysis does not change the effect of variables known to have an influence on dropout, such as grades, gender and social background, but it contributes to further explain who are at risk of dropout. This implies that models for dropout and retention must also take such external factors into account, not just consider what happens at university, as in model of student departure.     

Jugendliche zwischen Entwicklung und Entfaltung

Der Beitrag thematisiert jugendliche Orientierungsmuster zur Ausgestaltung der Lebensphase Jugend und deren Ver?nderung über die Zeit. Diese entstehen im komplexen Zusammenhang von wahrgenommenen Ressourcen, Einstellungen und Erwartungen Jugendlicher im Hinblick auf die Anforderung der Bew?ltigung von Entwicklungsaufgaben. Zur Abbildung dieser Muster wird auf zwei zentrale Dimensionen zurückgegriffen: auf Entfaltungsorientierung, die den Moratoriumsgedanken, und Entwicklungsorientierung, die den transitiven Charakter der Jugendphase widerspiegelt. Aus der Kombination der Orientierungen Entwicklung und Entfaltung im Anschluss an die Verknüpfung des Transitions-und Moratoriumsgedankens lassen sich vier Typen ableiten. Die Zugeh?rigkeit zu einem Typ ist nicht als statisch zu fassen, sondern ver?ndert sich entsprechend der zunehmenden Bew?ltigung von Entwicklungsaufgaben. Die Ergebnisse veranschaulichen die weitreichende Bedeutung beruflicher Orientierungen Jugendlicher im Zusammenhang mit dem bevorstehenden übergang in den Beruf, die gleichsam Auswirkungen für den gesamten Komplex jugendlicher Orientierungsmuster (Typen) zur Gestaltung der Jugendphase zeitigen.     

Collaboration between a child telephone helpline and sexual and reproductive health and rights organisations in Senegal: lessons learned

This study identifies lessons learned from a collaboration between a child telephone helpline and sexual and reproductive health and rights (SRHR) organisations in Senegal established in the context of an SRHR programme for young people. We assessed how helpline operators are equipped to address sexual health and rights issues with young people, what the relevant skills of operators are, and to what extent referral to sexual and reproductive health (SRH) service providers took place. A documentary review, a vignette study and interviews with six key informants and all seven operators took place. The collaboration led to promising initiatives, such as the provision of SRH training, the exchange of staff, referral to SRH service providers. However, the counselling advice provided by operators was not always in line with the rights-based approach and responses were influenced by underlying norms concerning young people’s sexuality. Additionally, concerns about confidentiality were noted. The collaboration was an innovative attempt to respond to young people’s limited access to SRHR information and services but there is a need for more in-depth training of helpline operator’s skills and the development of a standardised rights-based counselling manual.     

Influence of word meaning on the acquisition of a reading vocabulary in second-grade children

The acquisition of a reading vocabulary for abstract and concrete words was examined in 62 second-grade children. Words had been learned as part of a basal reader program or as part of outside reading. Word recognition speed and reading accuracy were examined for abstract and concrete words using lexical decision and word naming tasks. The size of the concreteness effect was similar for both processing tasks. In neither task did concreteness influence reaction times, but abstract words were read with less accuracy than concrete words in both tasks. Further, these concreteness effects in reading accuracy were larger for words that were part of a basal reading program than for words acquired during free reading. We conclude that word meaning influences the entry of words at a time when children are developing a sizeable reading vocabulary.     

Enhancement of biosensing performance in a droplet-based bioreactor by in situ microstreaming

A droplet-based micro-total-analysis system involving biosensor performance enhancement by integrated surface-acoustic-wave (SAW) microstreaming is shown. The bioreactor consists of an encapsulated droplet with a biosensor on its periphery, with in situ streaming induced by SAW. This paper highlights the characterization by particle image tracking of the speed distribution inside the droplet. The analyte-biosensor interaction is then evaluated by finite element simulation with different streaming conditions. Calculation of the biosensing enhancement shows an optimum in the biosensor response. These results confirm that the evaluation of the Damköhler and Peclet numbers is of primary importance when designing biosensors enhanced by streaming.It has been pointed out that biosensing performances can be limited by the diffusion of the analytes near the sensing surface.¹ In the case of low Peclet number hydrodynamic flows, typical of microfluidic systems, molecule displacements are mainly governed by diffusive effects that affect time scales and sensitivity. To overcome this problem, the enhancement of biosensor performance by electrothermal stirring within microchannels was first reported by Meinhart et al.² Other authors^{3, 4} numerically studied the analyte transport as a function of the position of a nanowire-based sensor inside a microchannel, stressing on the fact that the challenge for nanobiosensors is not the sensor itself but the fluidic system that delivers the sample. Addressing this problem, Squires et al.⁵ developed a simple model applicable to biosensors embedded in microchannels. However, the presented model is limited to the case of a steady flow. The use of surface-acoustic waves (SAWs) for stirring in biomicrofluidic and chemical systems is becoming a popular investigation field,^{6, 7, 8, 9} especially to overcome problems linked to steady flows by enhancing the liquid∕surface interaction.^{1, 10, 11} The main challenges that need to be addressed when using SAW-induced stirring are the complexity of the flow and its poor reproducibility. However, some technical solutions were proposed to yield a simplified microstreaming. Yeo et al. presented a centrifugation system based on SAW that produces the rotation of the liquid in a droplet in a reproducible way by playing on the configuration of the transducers and reflectors,¹² and presented a comprehensive experimental study of the three-dimensional (3D) flow that causes particle concentration in SAW-stirred droplets,¹³ revealing the presence of an azimuthal secondary flow in addition to the main vortexlike circular flow present in acoustically stirred droplets. The efficiency of SAW stirring in microdroplets to favorably cope with mass transport issues was finally shown by Galopin et al.,¹⁴ but the effect of the stirring on the analyte∕biosensor interaction was not studied. It is expected to overcome mass transport limitations by bringing fresh analytes from the bulk solution to the sensing surface.The studied system, described in Fig. ​Fig.1,1, consists of a microliter droplet microchamber squeezed between a hydrophobic piezoelectric substrate and a hydrophobic glass cover. Rayleigh SAWs are generated using interdigitated transducers (interdigital spacing of 50 μm) laid on an X-cut LiNbO₃ substrate.^{1, 15, 16} The hydrophobicity of the substrate and the cover are obtained by grafting octadecyltrichlorosilane (OTS) self-assembled monolayers (contact angle of 108° and hysteresis of 9°). To do so, the surface is first hydroxylized using oxygen plasma (150 W, 100 mT, and 30 sccm³ O₂) during 1 min and then immersed for 3 h into a 1 mM OTS solution with n-hexane as a solvent.Open in a separate windowFigure 1(a) General view of the considered system. (b) Mean value of the measured speeds within the droplet as a function of the inlet power before amplification.When Rayleigh waves are radiated toward one-half of the microchamber, a vortex is created in the liquid around an axis orthogonal to the substrate due to the momentum transfer between the solid and the liquid. This wave is generated under the Rayleigh angle into the liquid.Speed cartographies of the flow induced in the droplet are realized using the particle image tracking technique for different SAW generation powers. To do so, instantaneous images of the flow are taken with a high-speed video camera at 200 frames∕s and an aperture time of 500 μs on a 0.25 μl droplet containing 1 μm diameter fluorescent particles. Figure ​Figure11 shows the mean speed measured in the droplet as a function of the inlet power. The great dependence of the induced mean speed with the SAW power enables a large range of flow speeds in the stirred droplet. Moreover, the flow was visualized with a low depth of field objective. It was found to be circular and two dimensional (2D) in a large thickness range of the droplet.The binding of analytes to immobilized ligands on a biosensor is a two step process, including the mass transport of the analyte to the surface, followed by a complexation step,Abulk↔kmAsurface+B↔ka,kdAB(1)with k_m as the constant rate for mass transport from and to the sensor, and k_a and k_d as the constant rates of association and dissociation of the complex.At the biosensor surface, the reaction kinetics consumes analytes but their transport is limited by diffusive effects. In this case, the Damköhler number brings valuable information by comparing these two effects. Calling the characteristic time of reaction and diffusion, respectively, τ_C and τ_M, the mixing time in diffusion regime can be approximated by τ_M≈h²∕D with D as the diffusion coefficient and h a characteristic length of the microchannel. Calling R_T the ligand concentration on the surface in mole∕m², the Damköhler number (D_a) can be written asDa=τMτC=kaRThD.(2)Depending on the type of reaction, the calculation of D_a helps determine if a specific biointeraction will benefit from a mass SAW-based microstreaming. If the Damköhler number is low, the reaction is slow compared to mass transport and the reaction will not significantly benefit from microstirring. For example, the hybridization of 19 base single stranded DNA in a microfluidic system with a characteristic length of 500 μm is characterized by a Damköhler number of 0.07 and is therefore not significantly influenced by mass transport. On the contrary, the binding of biotin to immobilized streptavidin is characterized by a D_a number of approximately 10⁴. In this case, the stirring solution will significantly improve the reaction rate.COMSOL numerical simulations were carried out to study the efficiency of the SAW stirring in the case of a droplet-based microbioreactor with a diameter of 1 mm. Assuming a 2D flow, the simulated model takes into account the convective and diffusive effects in the analyte-carrying fluid and the binding kinetics on the biosensor surface. This approach was thoroughly developed by Meinhart et al.²On the biosensor surface, the following equations are solved:∂B∂t=kacs(RT−B)−kdB,(3)∂B∂t=D|∂c∂y|y=0(4)with c as the local concentration of analytes in the droplet and B as the surface concentration of bound analytes on the biosensor surface. Simulation results show that a depleted zone is formed near the biosensor in the case of an interaction without stirring. This zone is characterized by a low concentration of analytes and results from the trapping of analytes on the biosensor surface, thus creating a concentration gradient on the vicinity of the biosensor. When stirring is applied, the geometry of the depleted zone is modified, as it is pushed in the direction of the flow. The geometry of the depleted zone then depends on many parameters, among which the diffusion coefficient D, the speed distribution of the flow (not only near the biosensor but also in the whole microfluidic system), and the reaction kinetics on the biosensor. In our case, which is assimilated to a simple circular flow, the depleted zone reaches a permanent state consisting of an analyte-poor layer situated in the exterior perimeter of the stirred droplet. The diffusion of analytes is then limited again by diffusion from the inner part of the droplet toward its exterior perimeter (see Fig. ​Fig.22).Open in a separate windowFigure 2(a) Mean concentration of bound analytes vs time for different mean flow speeds. (b) The obtained concentration profiles with and without circular stirring, t=10 000 s.The initial analyte and receptor concentrations are, respectively, 0.1 nM in the solution and 3.3×10⁻³ nM m on the biosensor surface, the diffusion coefficient is D=10⁻¹¹ m² s⁻¹, and the reaction constants are k_a=10⁶ M⁻¹ s⁻¹ and k_d=10⁻³ s⁻¹. Simulations show that the mean concentration of bound analytes highly increases with the flow speed, improving the efficiency of the biosensing device. To evaluate the benefits of in situ microstreaming with SAW, the same simulations were conducted for D_a numbers ranging from 10⁴ to 10⁸ M⁻¹∕s, by ranging the diffusion coefficient from 4×10⁻¹² to 4×10⁻⁹ m²∕s, and the association coefficient k_a from 10⁴ to 10⁸ M⁻¹∕s. The enhancement factor of analyte capture, defined as the ratio of the binding rate with streaming B and the binding rate without streaming B0, is plotted in Fig. ​Fig.33 for different values of D_a. Calculations are done in the case of a mean flow speed of 0.5 mm∕s.Open in a separate windowFigure 3(a) Enhancement factor (defined as the ratio between binding rate with streaming B and binding rate without streaming B0) for different Damkhöler numbers and (b) normalized enhancement factor for different Peclet numbers.One can notice the saturation of the enhancement factor curve for large value of D_a to the value of 3.5 for high D_a. This can be explained by the fact that for large k_a∕D_a ratios, the analytes, which normally require penetration in the depleted zone by diffusion, do not have time to interact with the biosensor when they pass in the vicinity of its surface. The efficiency of the streaming is then reduced for large values of D_a. In the case of our specific flow configuration, the enhancement factor reaches 3.2 for the interaction of streptavidin on immobilized biotin (D_a=10³).The reported simulation results can be compared to an experimental value obtained using the droplet-based surface plasmon resonance sensor streamed in situ using SAW reported by Yeo et al.¹² By monitoring the streptavidin∕biotin binding interaction on an activated gold slide, they showed that SAW stirring brings an improvement factor of more than 2. This difference can be accounted to the high complexity of the induced 3D flow, which was modeled in a simple manner in our calculations.Other factors must be taken into account when optimizing the improvement factor, such as the flow velocity and the characteristic length of the mixing. To do so, the Peclet number allows the comparison of the convective and diffusive effects.¹⁷ For δC a typical variation in concentration on the distance h, the Peclet number is given byPe=UhD.(5)A significantly high Peclet number causes a decrease in biosensing efficiency as the analytes do not have enough time to interact with the biosensing surface by diffusion through the analyte-poor layer. On the contrary, the case of a low Peclet number corresponds to the diffusion-limited problem. Therefore, for each Damköhler number, there is a Peclet number optimizing this factor. To illustrate this fact, Fig. ​Fig.3b3b shows the calculation of the enhancement factor as a function of the Peclet number for a given D_a.In this paper, we showed that surface loading of typical analytes on a droplet-based biosensor can be highly increased by SAW microstirring. The system permits the enhancement of the biosensing performances by the continuous renewal of the analyte-carrying fluid near the sensing surface. Thanks to mean flow speeds measured up to 1800 μm∕s, the SAW microstreaming can be beneficial to the biosensing of a large range of analyte∕ligand interactions. In addition to the biosensing performance improvement, such a method can be easily integrated in micro-micro-total-analysis systems, which makes it a convenient tool for liquid handling in future biochips.     

Comparing residence hall and independent living settings

The social environments of residence halls and independent off-campus living settings (such as apartments and houses) were compared. The off-campus settings had as much emphasis on cohesion and emotional support, and had more emphasis on independence, academic achievement, and the enhancement of intellectual and cultural pursuits. Despite these differences, students who stayed in residence halls throughout their four years of college, as compared to those who moved into independent housing, had higher educational aspirations and performed better academically, although they were somewhat more conservative and traditional (higher religious concern, more participation in campus activities, less alcohol consumption and impulse expression). Additional analyses indicated that college living settings influence differential student change and that some of their effects occur because students tend to select and create settings which help them to maintain their preferred personal characteristics.