RhoA is required for cortical retraction and rigidity during mitotic cell rounding

Mitotic cell rounding is the process of cell shape change in which a flat interphase cell becomes spherical at the onset of mitosis. Rearrangement of the actin cytoskeleton, de-adhesion, and an increase in cortical rigidity accompany mitotic cell rounding. The molecular mechanisms that contribute to this process have not been defined. We show that RhoA is required for cortical retraction but not de-adhesion during mitotic cell rounding. The mitotic increase in cortical rigidity also requires RhoA, suggesting that increases in cortical rigidity and cortical retraction are linked processes. Rho-kinase is also required for mitotic cortical retraction and rigidity, indicating that the effects of RhoA on cell rounding are mediated through this effector. Consistent with a role for RhoA during mitotic entry, RhoA activity is elevated in rounded, preanaphase mitotic cells. The activity of the RhoA inhibitor p190RhoGAP is decreased due to its serine/threonine phosphorylation at this time. Cumulatively, these results suggest that the mitotic increase in RhoA activity leads to rearrangements of the cortical actin cytoskeleton that promote cortical rigidity, resulting in mitotic cell rounding

Implicit Bias in Daily Perceptions and Legal Judgments

In today’s demonstration, we explored the audience’s positive and negative associations with blacks and whites. The demonstration is an adaptation of the Implicit Association Test (www.projectimplicit.net), a computer-based task designed to explore mental connections between various concepts. Participants were presented with a list of concepts (stereotypically black and white names, pleasant and unpleasant concepts) in a column down the middle of a screen along with the response categories (black/white or Pleasant/Unpleasant) along the left and right sides. When reading a word, participants were asked to categorize it by slapping the knee (left or right) that corresponds to the category displayed on the left or right side of the screen. Their task was to do this as fast as possible, correcting any mistakes before going forward, and raising their hand after completing the last word in the list. We then noted the amount of time for a critical mass of participants (approximately seventy-five percent) to complete each trial. In simple trials, either names or valenced words are displayed. In two critical trials, both names and valenced words were presented simultaneously in the middle of the screen. The trials differ based on the pairings of the response categories, and these trials tend to show a drastic difference in completion times. When participants were required to use the same hand to categorize black names and unpleasant words or white names and pleasant words, they tended to respond almost twice as quickly as when using the same hand to categorize black names and pleasant words or white names and unpleasant words. While there are individual differences among the respondents, the demonstration provided audible and visceral evidence of the trend. We then asked the audience to interrogate the methodological and cultural implications of the task, ultimately concluding that the test potentially reveals the fairly widespread implicit negative associations with blacks. With this working hypothesis, we next discussed the nature of racial bias and its implications for judgment in legal domains

Consistency of electron scattering data with a small proton radius

We determine the charge radius of the proton by analyzing the published low momentum transfer electron-proton scattering data from Mainz. We note that polynomial expansions of the form factor converge for momentum transfers squared below 4m(pi)(2), where m(pi) is the pion mass. Expansions with enough terms to fit the data, but few enough not to overfit, yield proton radii smaller than the CODATA or Mainz values and in accord with the muonic atom results. We also comment on analyses using a wider range of data, and overall obtain a proton radius R-E = 0.840(16) fm

Child Abuse Evidence: New Perspectives from Law, Medicine, Psychology & Statistics: Question and Answer Session

A transcript of the Question and Answer session during the University of Michigan Journal of Law Reform Symposium, Child Abuse Evidence: New Perspectives from Law, Medicine, Psychology & Statistics

Child Abuse Evidence: New Perspectives from Law, Medicine, Psychology & Statistics: Question and Answer Session

A transcript of the Question and Answer session during the University of Michigan Journal of Law Reform Symposium, Child Abuse Evidence: New Perspectives from Law, Medicine, Psychology & Statistics