What Makes an Online Instructional Video Compelling?

Video has supported education for many years, and in online courses instructional videos are often a key component. To learn more about compelling video, a team at the Columbia University School of Continuing Education examined analytics from the video hosting platform and recruited 10 students to participate in in-depth interviews. Drawing from both quantitative and qualitative data, emerging patterns provide some insight as to what characteristics of online videos students describe as compelling, and what types of videos receive the most views

Photoionization of Co+^{+} and electron-impact excitation of Co2+^{2+} using the Dirac R-matrix method

Modelling of massive stars and supernovae (SNe) plays a crucial role in understanding galaxies. From this modelling we can derive fundamental constraints on stellar evolution, mass-loss processes, mixing, and the products of nucleosynthesis. Proper account must be taken of all important processes that populate and depopulate the levels (collisional excitation, de-excitation, ionization, recombination, photoionization, bound-bound processes). For the analysis of Type Ia SNe and core collapse SNe (Types Ib, Ic and II) Fe group elements are particularly important. Unfortunately little data is currently available and most noticeably absent are the photoionization cross-sections for the Fe-peaks which have high abundances in SNe. Important interactions for both photoionization and electron-impact excitation are calculated using the relativistic Dirac Atomic $R$-matrix Codes (DARC) for low ionization stages of cobalt. All results are calculated up to photon energies of 45 eV and electron energies up to 20 eV. The wavefunction representation of Co III has been generated using GRASP0 by including the dominant 3d$^7$, 3d$^6$[4s, 4p], 3p$^4$3d$^9$ and 3p$^6$3d$^9$ configurations, resulting in 292 fine structure levels. Electron-impact collision strengths and Maxwellian averaged effective collision strengths across a wide range of astrophysically relevant temperatures are computed for Co III. In addition, statistically weighted level-resolved ground and metastable photoionization cross-sections are presented for Co II and compared directly with existing work.Comment: 11 pages, 8 figures and 4 table

Student experiences with instructional videos in online learning environments

Drawing upon qualitative methods of semi-structured interviews and observational talk-through interviews, this qualitative dissertation investigates the ways in which graduate students in an online course context experience online instructional videos. A conceptual framework of user experience and multimodality, as well as the framework of sense-making developed by McCarthy and Wright (2004) guided this study and data analysis. The findings of this dissertation have implications for how students are participating in, interacting with, and making sense of online learning environments. Some of the findings of this research include: (a) students do not necessarily experience course videos as discrete elements (or differentiate them with other aspects of the course); (b) the times and contexts in which students view instructional videos shifts (e.g., between home and commuting); (c) student motivations and expectations shape how they approach and orient themselves towards watching online course videos; and (d) multimodal design elements influence students’ meaning-making of online instructional videos. These data findings are all in support of the overarching conclusion of this dissertation, which is that students have significant agency in these online environments, and their meaning-making of online videos may not align with designers’ intentions. This conclusion argues against deterministic views of design. The emerging findings have design implications related to the creation of learning environments in online spaces, such as: (a) fully integrating videos within the broader instructional design of a course; (b) foregrounding the embedded context of instructional videos; and (c) accounting for the shifting times, places, and contexts in which viewers watch instructional videos. This dissertation is situated in the growing field of online education, in particular higher education, where significant money and resources are increasingly dedicated towards the development of online spaces while still much is unknown in relation to the design, experiences, and impact of these online learning environments

Zinc - 1,10-phenanthroline complexes and their analytical application

The use of ultraviolet spectrophotometry for quantitative inorganic analytical purposes has long remained unexploited. An extremely large number of complexes of metals have characteristic absorption properties in the visible portion of the spectrum and many colorimetric methods of analysis depend upon this fact. With the present availability of ultraviolet spectrophotometric equipment the charachteristic absorption properties of many colorless metallic complexes in the ultraviolet region of the spectrum should as conveniently be capable of similar utilization

pH electrode performance under automated management conditions

pH is frequently measured in laboratories, but to have confidence in the results it is necessary to know that it was measured properly. For an electrode to give accurate results it must be treated well and calibrated correctly. In this paper, an automated system for pH measurement is described; the system uses the operational pH scale and calibrates using two or three buffer solutions, taking proper account of the effects of temperature on the system. The system can be programmed with standard methods and procedures to ensure that the electrode gives the best possible performance. Calibrations and measurements within the system are reproducible, and the automated system is more robust than the manual pH meter, and requires less operator time