Electrometers measure electric charge, but there must be a fundamental speed limit to measuring one electric charge. Since there are no dimensional inputs to this question, the answer must be expressible in terms of the fundamental physical constants of Nature, e, h , m, c. In general the question should be posed without reference to any specific technology, but for definiteness, we analyze the...

may be due to an intact blood–brain barrier (BBB), which restricts entry of serum IgG into the CNS. It has recently been reported that AQP4-IgG can be present in serum several years before clinical onset of NMO. 7 In addition, experimental studies have shown induction of NMO-like histopathology by transfer of human AQP4-IgG to animals only provided BBB breakdown. 2 Further studies are needed to...

We have developed a wheel spinning detector for cognitive tutors that uses a simplified method compared to existing wheel spinning detectors. The detector reads a sequence of the correctness of applying particular skill performed by a student using the cognitive tutor. The response sequence is first fed to Bayesian knowledge tracing to compute a sequence of probability of mastery at each time a...

An estimate is derived for the absolute magnitude of BFKL pomeron exchange at t = 0. The analysis takes account of energy conservation and of the need realistically to model nonperturbative contributions to the BFKL integral from infrared regions. Experiment finds that there is little or no room for a significant BFKL term in soft processes, and this constrains its magnitude in hard and semihar...

4—8per 10000 infants develop autism (Gillberg et al, 1991).Given its rarity, it appearsuneconomical to attempt early detection in a random sample. A basic tenet of the present study is that the early detection of autism is both possible and economic. It is possible because findings from experimental psychology have shown us what to look for in toddlers if we want to detect autism early. First...