Refinement of the population and radial dependence of the spherical atomic valence shell is introduced in a general crystallographic least-squares program. The radial dependence is described by an expansioncontraction parameter K, which, in the nine data sets tested, indicates contraction of positively and expansion of negatively charged atoms in agreement with theoretical concepts such as those incorporated in Slater's analytical rules for atomic orbitals. H atoms appear more contracted than concluded previously on the basis of a comparison of X-ray and neutron thermal parameters of sucrose. An average value of 1.40 for the radial contraction of H is used in structures for which no neutron thermal parameters are available. The resuiting net charges are used to calculate X-ray molecular dipole moments whose magnitude and direction are in good agreement with theoretical and other experimental results, though some differences may be expected because of matrix effects. Net molecular charges in the one-dimensional conductor TTF-TCNQ agree with results obtained earlier by direct integration of the charge density over the molecular volume. A charge transfer from Si to V in the superconducting alloy V3Si is also in agreement with earlier results.

Amphibious mangrove killifish, Kryptolebias marmoratus (formerly Rivulus marmoratus), are frequently exposed to aerial conditions in their natural environment. We tested the hypothesis that gill structure is plastic and that metabolic rate is maintained in response to air exposure. During air exposure, when gills are no longer functional, we predicted that gill surface area would decrease. In the first experiment, K. marmoratus were exposed to either water (control) or air for 1 h, 1 day,1 week, or 1 week followed by a return to water for 1 week (recovery). Scanning electron micrographs (SEM) and light micrographs of gill sections were taken, and morphometric analyses of lamellar width, lamellar length and interlamellar cell mass (ILCM) height were performed. Following 1 week of air exposure, SEM indicated that there was a decrease in lamellar surface area. Morphometric analysis of light micrographs revealed that there were significant changes in the height of the ILCM, but there were no significant differences in lamellae width and length between any of the treatments. Following 1 week of recovery in water, the ILCM regressed and gill lamellae were similar to control fish, indicating that the morphological changes were reversible. In the second experiment, V̇CO2 was measured in fish continuously over a 5-day period in air and compared with previous measurements of oxygen uptake(V̇O2) in water. V̇CO2 varied between 6 and 10 μmol g–1 h–1 and was significantly higher on days 3, 4 and 5 relative to days 1 and 2. In contrast to V̇O2 in water, V̇CO2 in air showed no diurnal rhythm over a 24 h period. These findings indicate that K. marmoratus remodel their gill structures in response to air exposure and that these changes are completely reversible. Furthermore, over a similar time frame, changes in V̇CO2 indicate that metabolic rate is maintained at a rate comparable to that of fish in water, underlying the remarkable ability of K. marmoratus to thrive in both aquatic and terrestrial habitats.

Palladacycle dimers possessing bridging halides can be easily cleaved by using N-heterocyclic carbenes (NHCs) to generate novel monomeric complexes. The structure of one of these was determined by single-crystal diffraction study and consists of a square-planar coordination around the palladium center where the NHC ligand is trans to the amine of the palladacycle. The complex was found to be equally active in aryl amination and alpha-arylation of ketones even at very low catalyst loading (0.02 mol %). Primary and secondary alkyl/arylamines are equally active partners in coupling reactions. [reaction: see text]

Shyness and boldness has been considered a fundamental axis of human behavioural variation. At the extreme ends of this behavioural continuum subjects vary from being bold and assertive to shy and timid. Analogous patterns of individual variation have been noted in a number of species including fish. There has been debate on the nature of this continuum as to whether it depends on context. That is, whether it is domain-general (as in humans), or contextspecific. The purpose of our study was to test if shyness and boldness depends on context in rainbow trout, Oncorhynchus mykiss and to this end we estimated boldness in five different situations. Our data provide evidence of a shy-bold behavioural syndrome in rainbow trout. Bold trout tended to be bold in four situations when the context was similar (when the context concerned foraging). However, in a different context, exploring a swim flume, the ranking was entirely different. We suggest that shyness and boldness depends on context in rainbow trout.

In two separate experiments we investigated the effects of different types of suture material and patterns on wound healing in rainbow trout Oncorhynchus mykiss with and without transmitter implants. We used absorbable and nonabsorbable monofilament and braided silk sutures in simple interrupted and vertical mattress patterns to close 3-cm incisions on rainbow trout. Braided silk sutures and vertical mattress suture patterns caused significantly more tissue inflammation (P Ͻ 0.05) as shown by macroscopic analysis. However, there were no significant differences in the histology or strength of the wounds related to the type of suture material or the type of suture pattern used. Dummy radio transmitters compounded the inflammatory effect silk had on healing incisions compared with inflammation without transmitters.