Making working memory work: the effects of extended practice on focus capacity and the processes of updating, forward access, and random access.

We investigated the effects of 10h of practice on variations of the N-Back task to investigate the processes underlying possible expansion of the focus of attention within working memory. Using subtractive logic, we showed that random access (i.e., Sternberg-like search) yielded a modest effect (a 50% increase in speed) whereas the processes of forward access (i.e., retrieval in order, as in a standard N-Back task) and updating (i.e., changing the contents of working memory) were executed about 5 times faster after extended practice. We additionally found that extended practice increased working memory capacity as measured by the size of the focus of attention for the forward-access task, but not for variations where probing was in random order. This suggests that working memory capacity may depend on the type of search process engaged, and that certain working-memory-related cognitive processes are more amenable to practice than others.

Novel onset of a posttraumatic superficial temporal artery pseudoaneurysm.

Less than 200 cases of posttraumatic superficial temporal artery pseudoaneurysm have been described in the literature. The majority of these cases result from blunt head trauma and are diagnosed an average of three weeks following the inciting traumatic event. In this case report, we describe a superficial temporal artery pseudoaneurysm that developed and was diagnosed the same day of a blunt head trauma in a 54-year-old white male. This is the earliest formation/diagnosis of post-traumatic superficial temporal artery pseudoaneurysm yet reported in the literature. This case report demonstrates that this diagnosis should be kept in the list of differential diagnoses for a post-traumatic soft tissue mass of the face, even immediately following the traumatic event.

Report of the Howard Hughes Medical Institute's workshop on the performance of laboratory chemical hoods.

The Howard Hughes Medical Institute sponsored a workshop on laboratory chemical hoods on June 8, 9, and 10, 1998, that brought together 24 experts in the field of laboratory chemical hoods to critically assess the information known about hood performance. Workshop participants developed 31 consensus statements that reflect their collective views on the body of knowledge or lack thereof, for laboratory chemical hoods. The consensus statements fall into four broad categories: (1) hood selection, use, and operation; (2) hood and laboratory design issues; (3) ventilation system design issues; and (4) hood performance testing. The consensus statements include 26 statements on what is known and unknown about the performance of laboratory chemical hoods, 2 statements of definition, and 3 statements that reflect the participants' agreement not to agree. The brief commentary that follows each consensus statement provides guidance and recommendations.