We generalize the classical Cayley-Dickson doubling process starting with a quaternion algebra over a field F by allowing the scalar in the doubling to be an invertible element in the algebra. We investigate the resulting eight-dimensional algebras over F and show that they are division algebras for all scalars chosen in D outside of the base field F , if D is a division algebra.

The hypothesis that episodic memory retrieval can occur in parallel with other cognitive processes was tested in 2 experiments. Participants memorized words and then performed speeded cued recall (Experiment 1) or speeded yes-no recognition (Experiment 2) in a dual-task situation. The psychological refractory period design was used: The participant was presented with a single test item at vario...

The Dimension Action (DA) model asserts that the visual system is modular, and that each task involves multiple-response mechanisms rather than a unitary-response selection mechanism. The model has been supported by evidence from single-task interference paradigms. We use the psychological refractory period paradigm and show that dual-task performance can also be explained by the DA model. In 6...

In a seminal STOC’95 paper, Arya et al. conjectured that spanners for low-dimensional Euclidean spaces with constant maximum degree, hop-diameter O(logn) and lightness O(logn) (i.e., weight O(logn)· w(MST)) can be constructed in O(n logn) time. This conjecture, which became a central open question in this area, was resolved in the affirmative by Elkin and Solomon in STOC’13 (even for doubling m...

It has recently been demonstrated that a lateralized distractor that matches the individual's top-down control settings elicits an N2pc wave, an electrophysiological index of the focus of visual-spatial attention, indicating that contingent capture has a visual-spatial locus. Here, we investigated whether contingent capture required capacity-limited central resources by incorporating a continge...

It is widely acknowledged that visual input is processed along two anatomically and functionally distinct pathways--a ventral pathway for conscious perception and a dorsal pathway for action control. The present study investigated whether the apparent direct and unmediated processing in the dorsal stream is subject to capacity limitations. Specifically, we tested whether a simple dorsal task of...

wild almond (amygdalus scoparia) is one of the most important species that provides a variety of ecological functions in the zagros forest ecosystem. in this study, we investigated the effects of some seed treatments on the survival and growth of amygdalus scoparia after seed planting at different aspects and elevations under natural conditions. the seed pretreatments consisted in soaking them ...

Several nematicides have been used to disinfest rice seeds contaminated with the white tip nematode, Aphelenchoides besseyi. We measured the efficacy of a standard disinfestation treatment that consists of soaking seeds in an aqueous emulsion of fenitrothion or fenthion and subsequently air-drying the seeds. We also measured the efficacy of the same treatments but without addition of nematicide...