Links for 2012-05-03

I'll fill in more about each of these studies shortly, but note in both cases, the authors make very strong statements about the very existence of dark matter, including the quotations that begin this post. In fact, the National Geographic coverage of the second article states things even more strongly than the paper. Pavel Kroupa, the third author of the study, is quoted as saying, "It means that we have to completely and utterly rethink cosmology.... Cosmology is basically in a shambles now." You can probably guess already that I don't see things quite that way. I'm no expert on galactic dynamics (the purview of the first paper) or on structure formation (which the second focuses on), so if there are any problems with the data or methodologies, I can't spot them. (If any readers are experts and can provide more detailed analysis, please let me know.) However, there are a couple of general points I want to make before summarizing the cases for and against dark matter's existence.

Standards Based Grading (SBG), what is it? Let me just say that SBG is a different way of thinking about grades. In Standards Based Grading, the main idea is that the grade is a measure of what students understand. It is not a measure of how well the students are obedient and it is not a measure of how much effort the students put into homework. Now, just to be clear, I am not an expert on SBG. If SBG were a science, I would be an SBG engineer. If you want an expert, try Andy Rundquist or Shawn Cornally (and others too). But anyway, it seems like the popular thing to do right now is to share notes about how I implemented SBG this semester. Really, these are notes for myself as well as others.

Based on a national survey of PhD students at tier-one U.S. institutions, we provide insights into the career preferences of junior scientists across the life sciences, physics, and chemistry. We also show that the attractiveness of academic careers decreases significantly over the course of the PhD program, despite the fact that advisors strongly encourage academic careers over non-academic careers. Our data provide an empirical basis for common concerns regarding labor market imbalances. Our results also suggest the need for mechanisms that provide PhD applicants with information that allows them to carefully weigh the costs and benefits of pursuing a PhD, as well as for mechanisms that complement the job market advice advisors give to their current students.