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Selected AbstractsContext-dependent effects of hippocampal damage on memory in the shock-probe testHIPPOCAMPUS, Issue 1 2005Hugo Lehmann Abstract We assessed the role of the hippocampus in anterograde memory, using the shock-probe test. Rats with sham or neurotoxic lesions of the hippocampus were given a shock-probe acquisition session during which each time they contacted a probe they received a shock; 24 h later, the rats were given a second shock-probe session to test their retention, but in this instance the probe was not electrified. Rats were tested in either the same context as the one used during acquisition or in a different context. The hippocampal lesions impaired avoidance of the probe and burying on the retention test, suggesting that the lesions induced anterograde amnesia. However, the impairment was context dependent. The hippocampal lesions impaired avoidance only when the rats were tested in the context in which they received the conditioning. The results of the shock-probe test suggest that the anterograde amnesia following hippocampal lesions is due mainly to an inability to associate the context with the shock more than to an inability to associate the probe with shock. © 2004 Wiley-Liss, Inc. [source] A reexamination of corporate risks under shadow costs of incomplete informationINTERNATIONAL JOURNAL OF FINANCE & ECONOMICS, Issue 1 2001Mondher Bellalah G3; G31; G32; G33 Abstract The valuation of the firm and its assets has been done for a long time in the classic context of complete information. Several empirical tests of the main valuation methods reveal a divergence between theoretical prices and observed prices. These deviations might be explained by the standard assumptions of complete information. It is possible to introduce information uncertainty as done by Merton and by Bellalah in the reexamination of corporate risks in the presence of information costs. The concept of risk is useful in modelling the value of the firm and its business risk and in the definition of the required rates of return and the cost of capital of corporations. However, the main well-known results ignore information uncertainty as defined by Merton. Using the main results from the study of Modigliani and Miller and the implications of Merton's model, we give expressions for the cost of capital and the value of the firm's equity and debt in the presence of information costs. We reexamine the relationships between interrelated risks in the same context. We introduce information costs in the computation of the cost of capital and in the pricing of equity in an option framework. When there are no information costs, the main relationships reduce to the classic results in the literature. Copyright © 2001 John Wiley & Sons, Ltd. [source] Technical Note: Accounting for anatomical symmetry in the first-order optical character of left and right eyesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 4 2007W. F. Harris Abstract In quantitative analyses of the optical character of eyes (and related systems) it is sometimes necessary to deal with left and right eyes in the same context. In accounting for anatomical symmetry (mirror symmetry in the mid-sagittal plane) one treats a cylinder axis at 20°, say, in a left eye as equivalent to an axis at 160° in a right eye. But this is only one aspect of the linear optical character of an eye. The purpose of this note is to show how to account for anatomical symmetry in the linear optical character of eyes in general. In particular the note shows how to modify the optical properties of left (or right) eyes so that anatomical symmetry is accounted for in quantitative analyses in contexts in which both left and right eyes are involved. [source] Motives for giving information in non-work contexts and the expectations of reciprocity.PROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2007The case of environmental activists Information sharing stands for a two-way activity in which information is given and received in the same context. The present study reviews information sharing from the viewpoint of information giving. The empirical analysis draws on interviews with twenty environmental activists in Finland, 2005. Three major motives for information giving in non-work contexts were identified: first, seredipitous altruism to provide help to other people, second, pursuit of the ends of seeking information by proxy, and third, duty-driven needs characteristic of persons elected to positions of trust. Since in most cases information giving was driven by altruistic motives, the lack of reciprocity did not in practice weaken the motives for information giving. However, in the case of sensitive information, information giving tends to be restricted by calculations of the risk of information leakage against benefits obtained from the personally rewarding experience of providing important information to others. [source] AtKC1, a conditionally targeted Shaker-type subunit, regulates the activity of plant K+ channelsTHE PLANT JOURNAL, Issue 1 2008Geoffrey Duby Summary Amongst the nine voltage-gated K+ channel (Kv) subunits expressed in Arabidopsis, AtKC1 does not seem to form functional Kv channels on its own, and is therefore said to be silent. It has been proposed to be a regulatory subunit, and to significantly influence the functional properties of heteromeric channels in which it participates, along with other Kv channel subunits. The mechanisms underlying these properties of AtKC1 remain unknown. Here, the transient (co-)expression of AtKC1, AKT1 and/or KAT1 genes was obtained in tobacco mesophyll protoplasts, which lack endogenous inward Kv channel activity. Our experimental conditions allowed both localization of expressed polypeptides (GFP-tagging) and recording of heterologously expressed Kv channel activity (untagged polypeptides). It is shown that AtKC1 remains in the endoplasmic reticulum unless it is co-expressed with AKT1. In these conditions heteromeric AtKC1-AKT1 channels are obtained, and display functional properties different from those of homomeric AKT1 channels in the same context. In particular, the activation threshold voltage of the former channels is more negative than that of the latter ones. Also, it is proposed that AtKC1-AKT1 heterodimers are preferred to AKT1-AKT1 homodimers during the process of tetramer assembly. Similar results are obtained upon co-expression of AtKC1 with KAT1. The whole set of data provides evidence that AtKC1 is a conditionally-targeted Kv subunit, which probably downregulates the physiological activity of other Kv channel subunits in Arabidopsis. [source] Review of polyhedral distortions as a multi-scale minimization of the electric polarization and their correlations with physical propertiesACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2006Abderrahim Benabbas The Jahn,Teller (JT) and non-Jahn,Teller polyhedral distortions are reviewed within the same context, based on a multi-scale minimization of the electric polarization by handling formal ionic valences and valence electron density. This model is applied to tetragonal distortions of octahedra, particularly in K2NiF4 structures with different formula types, along with doping. The predictions are always in good agreement with the observed data. In particular, the ferrodistortive order of JT distortions is obtained from formal charge polarizations, while the antiferrodistortive one is adopted when only the valence electron density is involved. The correlations between physical properties and octahedral elongations through the crystal structures on one side and chemical compositions on the other side are discussed according to this model for high- Tc cuprate superconductors and CMR manganites. [source] A look at the abandoned contributions to cosmology of Dirac, Sciama, and DickeANNALEN DER PHYSIK, Issue 1 2009A. Unzicker Abstract The separate contributions to cosmology of the above researchers are revisited and a cosmology encompassing their basic ideas is proposed. We study Dirac's article (1938) on the large number hypothesis, Sciama's proposal (1953) of realizing Mach's principle, and Dicke's considerations (1957) on a flat-space representation of general relativity with a variable speed of light (VSL). Dicke's tentative theory can be formulated in a way which is compatible with Sciama's hypothesis on the gravitational constant G. Additionally, such a cosmological model is shown to satisfy Dirac's second ,large number' hypothesis on the total number of particles in the universe being proportional to the square of the epoch. In the same context, Dirac's first hypothesis on an epoch-dependent G , contrary to his prediction , does not necessarily produce a visible time dependence of G. While Dicke's proposal reproduces the classical tests of GR in first approximation, the cosmological redshift is described by a shortening of measuring rods rather than an expansion of space. Since the temporal evolution of the horizon R is governed by , the flatness and horizon problems do not arise in the common form. [source] Crying and Infant Abuse in Rhesus MonkeysCHILD DEVELOPMENT, Issue 2 2000Dario Maestripieri This study investigated the relation between crying and infant abuse in group-living rhesus monkeys (Macaca mulatta). The subjects were 10 abusive mothers with their infants and 10 control mother , infant pairs. Abused infants cried more frequently than controls in the first 12 weeks of life, even when cries immediately following abuse were excluded from the analysis. The coos of 5 abused infants differed from those of 5 controls in several acoustic parameters, whereas their screams and geckers were acoustically similar, when recorded in the same context. Abusive mothers were less likely than control mothers to respond positively to the cries of their infants. Although infant cries may increase the probability of abuse being repeated, infant crying per se does not appear to be a major determinant of abuse. [source] | ||||||||||