4205systems, one should use azethoxyl, rather than doxyl, nitroxides.Acknowledgment. We are grateful to Professor Z. Luz for helpful discussions. This study was made possible in part by funds granted by the Charles H. Revson Foundation (to E.M.). The statements made and views expressed, however, are solely the responsibility of the author (E.M.).The effect of solvent viscosity and temperature on the fluorescence quantum yield of p-(dimethylamino)benzylidenemalononitrile (1) and julolidinemalononitrile (3) has been studied in ethyl acetate, dimethyl phthalate, and glycerol. In the low-viscosity solvent, ethyl acetate, when temperature and viscosity variations are studied, a hydrodynamic model with a stick boundary condition gives an accurate and consistent description of the dynamics of the torsional motion of the probes. However, in medium-and high-viscosity solvents deviations from the hydrodynamic model are seen. In these solvents the free-volume concept was found to provide an accurate description of the solvent viscosity-temperature behavior and the probe torsional relaxation dynamics.

Mobile technology is increasingly used both in and out of school classrooms by students to remain actively engaged in learning and extend their learning. Developments in mobile technology have made it possible to access and interact with learning resources, other learners and teachers in ways not possible just a few years ago. Instructional designers and teachers struggle to maintain understandings of how changes in technology impact student interactions and learning engagement. Instead of focusing on particular tools, instructional designers and teachers should focus on the design of the learning environment to gain understanding of what students are doing while engaged in learning. The Seven-Traits of a Learning Environment framework is introduced here to help educators develop more effective and engaging instructional design for mobile learning environments. The SAMR technology integration model is discussed as a potential tool to help measure student engagement through the lens of the 7-Traits framework.Connectivist learning theory explains how knowledge acquisition depends on connected information sources that include people, social networks, search engines, media resources, and other digital media. Siemens wrote that connected learners regularly inquire, collaborate, share work and express themselves while developing and strengthening knowledge sources, which can be found internally in cognitive networks, and externally in connected networks [3]. The actions involved in maintaining these knowledge connections increase the complexity of these networks and enables learners to construct new and meaningful understandings. Learning in a connected environment is typically public and non-linear and assessments are based on student generated and collaborative works [4]. By utilizing common mobile communication and search tools, students can create, develop, and strengthen connections between different information sources [5]. The tools aid student thinking by providing ways to help them decrease mental effort while processing information and creating long-term knowledge. As students are practically always in possession of a mobile device, they are capable of increasing overall participation in discussions, asking and answering questions, sharing and reviewing work, or conducting and analyzing research. Reciprocal DeterminismAccording to Bandura, learning can be observed through the triadic relationships of behavior, psychology and situation [11]. From a practical point of view instructional designers or teachers can observe this in how the students act, behave and process information in different situations. Learning is dependent on how these factors interact; changes in one impact the other two. In mobile learning environments, learner engagement is witnessed when students use their mobile learning in different contexts to build and personalize their knowledge. They may send messages, share pictures and work, ask for help, inquire, watch videos, or even play games in different ways to help their learning. Because ...

Einfluß von Viskosität protischer und aprotischer Lösungsmittel und der Temp. auf die Fluoreszenz‐Quantenausb.