Neural Correlates of Letter-String Length and Lexicality during Reading in a Regular Orthography

Behavioral studies have shown that short letter strings are read faster than long letter-strings and words are read faster than nonwords. Here, we describe the dynamics of letter-string length and lexicality effects at the cortical level, using magnetoencephalography, during a reading task in Finnish with long (eight-letter) and short (four-letter) word/nonword stimuli. Length effects were observed in two spatially and temporally distinct cortical activations: (1) in the occipital cortex at about 100 msec by the strength of activation, regardless of the lexical status of the stimuli, and (2) in the left superior temporal cortex between 200 and 600 msec by the duration of activation, with words showing a smaller effect than nonwords. A significant lexicality effect was also evident in this later activation, with stronger activation and longer duration for nonwords than words. There seem to be no distinct cortical areas for reading words and nonwords. The early length effect is likely to be due to the low-level visual analysis common to all stimulus letter-strings. The later lexicality and length effects apparently reflect converging lexico-semantic and phonological influences, and are discussed in terms of dual-route and single-route connectionist models of reading.Peer reviewe

Clarification of Pseudologia Fantastica, a study of two cases of fantastic pseudology.

The term pseudologia fantastica has been fairly widely used despite the lack of consensus as to its definition. Little attention has been paid to its diagnostic significance. As a presenting symptom it can be confused with delusional psychosis, confabulation, malingering, or mere lying. In this article the literature is briefly reviewed, and the diagnostic significance of pseudologia fantastica in cases of neuropsychiatric, delusional, and personality disorders is illustrated with two clinical vignettes.</p

Nuclear antiferromagnetism in rhodium metal at positive and negative nanokelvin temperatures

We have measured the dynamic susceptibility of polycrystalline rhodium foils down to 280 pK and up to -750 pK. These record-low and -high nuclear spin temperatures were reached by adiabatic demagnetization using initial polarizations of 83 and -60%. At T>0, the static susceptibility, integrated from NMR spectra, displays an antiferromagnetic Curie-Weiss law, with θ=-1.8±0.3 nK. At T<0, a crossover from ferro- to antiferromagnetic tendency is found around -6 nK. We obtain Jnn/h=-17±3 Hz and Jnnn/h=10±3 Hz if only nearest and next nearest neighbor interactions are assumed.Peer reviewe

Spin dynamics in highly polarized silver at negative absolute temperatures

We have studied the spin dynamics of highly polarized silver nuclei at negative absolute temperatures up to inverted polarizations p≃-70%. The measured NMR spectra at B=0.4 and 0.8 mT display a clear inverted suppression-enhancement effect, arising from an interaction between the two spin species, 107Ag and 109Ag. The averaged interaction-field description accounts well for the intensity ratio of the isotopic NMR lines. The frequency difference of the absorption maxima has been used to study the merging and repulsion of the NMR modes at large negative polarizations. At B=0.2 mT, our spectra display only a single exchange-merged line, indicating that the two isotopes act as like spins. The transition from a single NMR line to two separate lines proceeds in a similar fashion as at positive temperatures. No effects attributable to the tendency of ferromagnetic alignment of spins at T<0 were observed.Peer reviewe

Leaded tin bronzes: the effects of casting method on dry sliding behaviour

In metal-to-metal sliding bearing applications, leaded tin bronzes are widely known as materials with excellent seizure resistance. In conditions of boundary or dry lubrication, lead may smear across the sliding surface, preventing surface contact and catastrophic seizure. The aim of this study was to determine the effects of casting method on the dry sliding behaviour of leaded tin bronzes. Continuous cast, centrifugally cast, and sand cast leaded tin bronze samples with varying lead contents were subjected to pin-on-disk- testing. It was found that casting method has a significant effect on the wear behaviour of leaded tin bronzes in dry sliding conditions. With continuous cast samples, the dominant wear mode was rapid, stable microcracking along copper/lead interfacial boundaries. With centrifugally and sand cast samples, wear occurred more slowly and erratically through the formation of transfer layers. The dominant wear mode was found to be connected to the coarseness of the distribution of lead particles in the copper matrix