Tornadoes in a Microchannel

In non-dilute colloidal suspensions, gradients in particle volume fraction result in gradients in electrical conductivity and permittivity. An externally applied electric field couples with gradients in electrical conductivity and permittivity and, under some conditions, can result in electric body forces that drive the flow unstable forming vortices. The experiments are conducted in square 200 micron PDMS microfluidic channels. Colloidal suspensions consisted of 0.01 volume fraction of 2 or 3 micron diameter polystyrene particles in 0.1 mM Phosphate buffer and 409 mM sucrose to match particle-solution density. AC electric fields at 20 Hz and strength of 430 to 600 V/cm were used. We present a fluid dynamics video that shows the evolution of the particle aggregation and formation of vortical flow. Upon application of the field particles aggregate forming particle chains and three dimensional structures. These particles form rotating bands where the axis of rotation varies with time and can collide with other rotating bands forming increasingly larger bands. Some groups become vortices with a stable axis of rotation. Other phenomena showed include counter rotating vortices, colliding vortices, and non-rotating particle bands with internal waves

Norming in Administrative Law

How do regulatory agencies decide how strictly to regulate an industry? They sometimes use cost-benefit analysis or claim to, but more often the standards they invoke are so vague as to be meaningless. This raises the question whether the agencies use an implicit standard or instead regulate in an ad hoc fashion. We argue that agencies frequently use an approach that we call “norming.” They survey the practices of firms in a regulated industry and choose a standard somewhere within the distribution of existing practices, often no higher than the median. Such a standard burdens only the firms whose practices lag the industry. We then evaluate this approach. While a case can be made that norming is appropriate when a regulatory agency operates in an environment of extreme uncertainty, we argue that on balance norming is an unwise form of regulation. Its major attraction for agencies is that it minimizes political opposition to regulation. Norming does not serve the public interest as well as a more robust standard like cost-benefit analysis

Regulation, Unemployment, and Cost-Benefit Analysis

Regulatory agencies take account of the potential unemployment effects of proposed regulations in an ad hoc, theoretically incorrect way. Current practice is to conduct feasibility analysis, under which the agency predicts the unemployment effects of a proposed regulation, and then declines to regulate (or weakens the proposed regulation) if the unemployment effects exceed an unarticulated threshold, that is, seem “too high.” Agencies do not reveal the threshold, do not explain why certain unemployment effects are excessive, and do not explain how they compare unemployment effects and the net benefits of the regulation. Many agencies also predict unemployment effects incorrectly. The proper approach is for agencies to incorporate unemployment effects into cost-benefit analysis by predicting the amount of unemployment that a regulation will cause and monetizing that amount. Recent economic studies suggest that monetized cost of unemployment is significant, possibly more than $100,000 per worker. If agencies used this figure, there could be significant consequences for a wide variety of regulations

Using stimulants to treat ADHD-related emotional lability

Emotional lability, or sudden strong shifts in emotion, commonly occurs in youth with attention-deficit/hyperactivity disorder. Although these symptoms are impairing and disruptive, relatively little research has addressed their treatment, likely due to the difficulty of reliable and valid assessment. Promising signals for symptom improvement have come from recent studies using stimulants in adults, children and adolescents. Similarly, neuroimaging studies have begun to identify neurobiological mechanisms underlying stimulants’ impact on emotion regulation capacities. Here, we review these recent clinical and neuroimaging findings, as well as neurocognitive models for emotional lability in ADHD, issues of relevance to prescribers and the important role of psychiatric comorbidity with treatment choices

Should Regulation Be Countercyclical?

Politicians and commentators have from time to time proposed that regulations be suspended or delayed during recessions because of their adverse impact on employment. We evaluate this argument from within a macroeconomic framework. When the business cycle is taken into account, it is possible that regulations should be weakened during downturns and strengthened during upturns, along the lines of stimulus policy, which normally takes the form of countercyclical adjustments to taxes or the money supply. However, countercyclical regulation will normally be a less efficient means of stimulus. For that reason, it should be used in relative narrow conditions, and when the other stimulus instruments are either ineffective on their own terms or politically infeasible

Cost-Benefit Analysis and the Judicial Role

The two most vilified cases in administrative law are Business Roundtable v Securities and Exchange Commission and Corrosion Proof Fittings v Environmental Protection Agency. In Business Roundtable, the DC Circuit struck down the SEC’s proxy access rule because the agency’s cost-benefit analysis of the regulation, in the court’s view, was defective. In Corrosion Proof Fittings, the Fifth Circuit struck down an EPA regulation of asbestos products on the same grounds. Nearly all scholars who have written about these cases have condemned them. We argue that the courts acted properly. The regulators’ cost-benefit analyses were defective, seriously so; and the courts were right to require the agencies to show that their regulations passed an adequate cost-benefit analysis. We further argue that the trajectory of law and policy is consistent with our view. Corrosion Proof Fittings and Business Roundtable are harbingers rather than errors—harbingers of an era of enhanced judicial review of cost-benefit analysis