A. G. Rigas

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Humans show implicit memory for complex spatial layouts, which aids in subsequent processing of these layouts. Research efforts in the past 5 years have focused primarily on a single session of training involving a dozen repeated displays. Yet every day, people encounter many more visual layouts than were presented in such experiments. In this study, we(More)
BACKGROUND Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle disorder characterized by hyperammonemia resulting in white matter injury and impairments in working memory and executive cognition. OBJECTIVE To test for differences in BOLD signal activation between subjects with OTCD and healthy controls during a working memory task. (More)
We performed a statistical analysis of 290± 500 keV ion data obtained by IMP-8 during the years 1982±1988 within the earth's magnetosheath and analysed in detail some time periods withdistinct ion bursts. These studies reveal the following characteristics for magnetosheath 290±500 keV energetic ions: (a) the occurrence frequency and the ¯ux of ions increase(More)
In one approach to spectral estimation, a sample record is broken into a number of disjoint sections, or data is collected over a number of discrete trials. Spectral parameters are formed by averaging periodograms across these discrete sections or trials. A key assumption in this approach is that of weak stationarity. This paper describes a simple test that(More)
Humans process a visual display more efficiently when they encounter it for a second time. A previously perceived object, now presented very briefly, is correctly identified more accurately than a new object, showing priming (Tul-ving & Schacter, 1990). Such perceptual facilitation is seen not only for isolated shapes or words, but also for complex visual(More)
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