The Distances of the Magellanic Clouds

The present status of our knowledge of the distances to the Magellanic Clouds is evaluated from a post-Hipparcos perspective. After a brief summary of the effects of structure, reddening, age and metallicity, the primary distance indicators for the Large Magellanic Cloud are reviewed: The SN 1987A ring, Cepheids, RR Lyraes, Mira variables, and Eclipsing Binaries. Distances derived via these methods are weighted and combined to produce final "best" estimates for the Magellanic Clouds distance moduli.Comment: Invited review article to appear in ``Post Hipparcos Cosmic Candles'', F. Caputo & A. Heck (Eds.), Kluwer Academic Publ., Dordrecht, in pres

The Microbiome, Probiotics, and Prebiotics

In this chapter, there will be discussion of the skin microbiome formation, composition, function, and regional topographical differences. Similarly, the gut microbiome will be reviewed, and dysbiosis at each site as well as the consequences of such dysbiosis will be entertained. Specifically, the interaction between the skin microbiome and gut microbiome will be discussed with respect to acne and rosacea. Although information to date is limited with respect to treatment options, therapeutic interventions which may work through microbial systems will be presented. Finally, ideas for future research will be put forth

The Psychometric Modeling of Scientific Reasoning: a Review and Recommendations for Future Avenues

Psychometric modeling has become a frequently used statistical tool in research on scientific reasoning. We review psychometric modeling practices in this field, including model choice, model testing, and researchers’ inferences based on their psychometric practices. A review of 11 empirical research studies reveals that the predominant psychometric approach is Rasch modeling with a focus on itemfit statistics, applied in a way strongly similar to practices in national and international large-scale educational assessment programs. This approach is common in the educational assessment community and rooted in subtle philosophical views on measurement. However, we find that based on this approach, researchers tend to draw interpretations that are not within the inferential domain of this specific approach and not in accordance with the related practices and inferential purposes. In some of the reviewed articles, researchers put emphasis on item infit statistics for dimensionality assessment. Item infit statistics, however, cannot be regarded as a valid indicator of the dimensionality of scientific reasoning. Using simulations as illustration, we argue that this practice is limited in delivering psychological insights; in fact, various recent inferences about the structure, cognitive basis, and correlates of scientific reasoning might be unwarranted. In order to harness its full potential, we make suggestions towards adjusting psychometric modeling practices to the psychological and educational questions at hand