Chronobiology Predicts Actual and Proxy Outcomes when Dipping Fails

Chronobiology predicts actual and proxy outcomes when dipping fails.

To the Editor: As a gauge of variability, dipping, based on day-night ratios of blood pressure, is much discussed,1 with 2194 hits in a search of the literature on the Internet. But, as compared with dipping, a classification based on chronobiological end points (such as the circadian amplitude and phase) interpreted in the light of reference values specified by gender and age offers superior d...

When Bellman's Principle Fails

We present several examples which show that the well known statements about Markov Decision Processes can fail if the loss function is not bounded.

When Sharing Fails

When Abstraction Fails

Reasoning about programs is mostly deduction: the reasoning from the abstract model to the concrete run. Deduction is useful because it allows us to predict properties of future runs—up to the point that a program will never fail its specification. However, even such a 100% correct program may still show a problem: the specification itself may be problematic, or deduction required us to abstrac...

When face recognition fails.

Two studies investigated recognition of pictures of faces, focusing on the effects of changes in appearance of the face from presentation to test and type of processing or encoding. Experiment 1 demonstrated that (a) previously seen faces changed in pose and facial expression were discriminated from "new" faces essentially as well as pictures identical at presentation and test; (b) major change...