This study investigates on a quantitative basis two strategies that can be used to increase the legibility distance of retroreflective traffic signs with negative luminance contrast legend or symbols at night. The first strategy involves the increase of the letter, numeral, or symbol size associated with a corresponding increase in the stroke width (representing the visual detail) and with an i...

People simply cannot do two things at once, as shown by research on the so-called psychological refractory period. A new neuroimaging study has now localized the response-selection bottleneck underlying the psychological refractory period to a frontoparietal network.

Let T : [0, 1] → [0, 1] be the doubling map and let 0 < a < b < 1. We say that an integer n ≥ 3 is bad for (a, b) if all n-cycles for T intersect (a, b). Let B(a, b) denote the set of all n which are bad for (a, b). In this paper we completely describe the sets: D2 = {(a, b) : B(a, b) is finite} and D3 = {(a, b) : B(a, b) = ∅}. In particular, we show that if b − a < 1 6 , then (a, b) ∈ D2, and ...

It is shown that next-nearest-neighbor interactions may lead to unusual paramagnetic or ferromagnetic phases which physical content is radically different from the standard phases. Actually there are several particles described by the same quantum field in a manner similar to the species doubling of the lattice fermions. We prove the renormalizability of the theory at the one loop level.

In this psychological refractory period (PRP) experiment, a tone (T1) was presented, followed by a visual target (T2) embedded in a bilateral display, and a speeded response was required for each target. The T1-T2 stimulus onset asynchrony (SOA) was 300, 650, or 1000 ms. Mean response time to T2 increased as SOA was reduced, replicating the well-known PRP effect. Importantly, the N2pc component...

A test of whether patients suffering from a severe closed-head injury (CHI) were affected by disproportionate dual-task costs compared to those of healthy control participants was carried out through a direct comparison of CHI effects on dual-task (psychological refractory period, or PRP) performance and on single-task performance. In the dual-task condition of the present experiment, independe...

The psychological refractory period (PRP) is a basic but important form of dual-task information processing. Existing serial or parallel processing models of PRP have successfully accounted for a variety of PRP phenomena; however, each also encounters at least 1 experimental counterexample to its predictions or modeling mechanisms. This article describes a queuing network-based mathematical mod...

For 30 years, A. G. Greenwald and H. G. Shulman's (1973) psychological refractory period (PRP) study has been cited as evidence for perfect timesharing with ideomotor (IM)-compatible tasks. Recently, M.-C. Lien, R. W. Proctor, and P. A. Allen (2002) failed to replicate these results and concluded that IM compatibility is neither necessary nor sufficient to eliminate the PRP effect. A. G. Greenw...

The present study examined whether the central bottleneck, assumed to be primarily responsible for the psychological refractory period (PRP) effect, is intact, bypassed, or shifted in locus with ideomotor (IM)-compatible tasks. In 4 experiments, factorial combinations of IM- and non-IM-compatible tasks were used for Task 1 and Task 2. All experiments showed substantial PRP effects, with a stron...

In this paper we derive the controlled center dynamics and synthesize stabilizing controllers for nonlinear discrete time systems with fold and period-doubling control bifurcations.