A typkal trial of this masking experiment in\·olves. in quick succession. presentation of five letters. evocation of an eye mowment. and presentation of a spatially localized mask. either a visual-pattern mask or a metacontrast ring. The effect of the mask is to suppress the report of the letter that stimulates the same retinal location, even though the mask appears to cO\'er or surround the letter whose position in real space it shares. "-tasking is. however. weaker when the eyes move than when they do not. An auxiliary experiment suggests that the spatial aspects of observable (reportable by S) stimulus persistence are unaffected by eye movements. and therefore that observable persistence differs from that susceptible to masking.

The usual univariate test for the repeated-measures effect in a one-way design rests upon an assumption of uniform variances and covariances. The standard test of this assumption is shown to have acceptable power only when the multivariate test of the hypothesis is essentially as powerful as the univariate test. A modified form of the univariate test, not requiring the assumption of uniformity, is compared to the multivariate test with respect to power. Depending on the variance-covariance structure of the data and the alternative hypothesis, the univariate test ranges from somewhat better to much worse than the multivariate test. There are possibly interesting experimental effects which the univariate test is virtually powerless to detect.

Identity management systems (IDMSs) are widely used to provision user identities while managing authentication, authorization, and data sharing within organizations and on the web. Traditional identity systems typically suffer from single points of failure, lack of interoperability, and privacy issues, such as enabling mass data collection and user tracking. Blockchain technology has the potential to alleviate these concerns: it can support the ability for users to control the custody of their own identifiers and credentials, enabling novel data ownership and governance models with built-in control and consent mechanisms. Hence, blockchain-based IDMSs, which could benefit both users and businesses, are beginning to proliferate. This work categorizes these systems into a taxonomy based on differences in blockchain architectures, governance models, and other salient features. Context is provided for the taxonomy through the description of related terms, emerging standards, and use cases while highlighting relevant security and privacy considerations. Keywords blockchain; data custody; data ownership; decentralized identifier; distributed ledger; identity management; public key infrastructure; self-sovereign identity; smart contract; user-controlled identity wallet; verifiable credential; zero-knowledge proof Disclaimer Any mention of commercial products or reference to commercial organizations is for information only; it does not imply recommendation or endorsement by the National Institute of Standards and Technology (NIST), nor does it imply that the products mentioned are necessarily the best available for the purpose.

Capillary pressure across a 50 μm bubble in a glass capillary is oscillated to measure the dynamic surface tension of lysolipids.