ALBERT

Notes: A sample of ombrotrophic peat from Moor House in northern England was extensively extracted with dilute nitric acid (pH 1) to free it of bound cations. Suspensions of the acid-washed peat (5–30 g l−1), prepared with different concentrations of background electrolyte (NaCl and KCl), were used to conduct batch acid–base titrations. A strong dependence of proton release on ionic strength (I) was observed, the apparent acid dissociation constant (pKapp) being found to decrease by approximately 1.0 for each tenfold increase in I. This behaviour could not be explained satisfactorily with Humic Ion-Binding Model VI, a discrete-site/electrostatic model of cation binding by humic substances, parameterized with data from laboratory studies on isolated samples. More success was obtained by abandoning the impermeable-sphere electrostatic submodel used in Model VI, and instead assuming the peat to consist of aggregates with fixed internal volume, and with counterion accumulation described by the Donnan model, as proposed by Marinsky and colleagues. The fixed-volume Donnan model (Model VI-FD) could also approximately explain other reported results from acid–base titrations of peat, including the effects on the titrations of complexing cations (Al, Ca, Cu). Copper titrations of the Moor House sample were performed using an ion-selective electrode, with peat suspensions in the acid pH range, at two ionic strengths, and in the presence of Al and Ca. The measured concentrations of Cu2+ were in the range 10−13−10−5 m. Model VI-FD provided reasonable fits of the experimental data, after optimization of the intrinsic binding constant for Cu, the optimized value being close to the default value derived previously from data referring to isolated humic substances. The optimized constants for Al and Ca, derived from their competition effects, were also close to their default values. Additional experiments were performed in which the centrifugation-depletion method was used to measure the binding of a cocktail of metals (Al, Ni, Cu, Zn, Cd, Eu, Pb) at a single pH. The model correctly predicted strong binding of Al, Cu, Eu and Pb, and weaker binding of Ni, Zn and Cd. For the strongly binding metals, the dissolved forms were calculated to be mainly due to complexes with dissolved humic matter, whereas the free ions (Ni2+, Zn2+, Cd2+) dominated for the weakly binding metals. Acid-washed soil appears to provide a valuable intermediate between isolated humic substances and untreated soil for the investigation of cation binding by natural organic matter in the natural environment.

Notes: Teleost fish are commonly used as model species in laboratory studies of behaviour and ecology. In comparison to other groups of vertebrates used routinely in such studies, however, relatively little attention has been paid to their environmental requirements from a welfare perspective. Fish naturally inhabit a wide variety of aquatic habitats that differ enormously in the range of light environments they provide, and light regime has enormous potential to affect behaviour. Yet the level and quality of illumination (in terms of intensity and wavelength spectrum) provided in experimental studies of fish behaviour is generally designed to maximize ease of recording by the observer. In addition, display or home aquaria provide illumination that maximizes the ‘viewing pleasure’ of the observer, and specialist lighting tubes are available to stimulate rapid plant growth and to ‘show off’ the colours of fish, rather than to provide ‘natural’ light environments. Here we present the results of three studies designed to examine the effects of light intensity, wavelength spectrum and their interactions on the behaviour of a model species commonly used in behavioural studies, the three-spined stickleback Gasterosteus aculeatus. Our aims are to determine whether unnatural light environments, generated by manipulating light intensity and wavelength spectrum, affect behaviour in ways that may lead to concern for the welfare of fish as research animals or pets.

Notes: The role of organisational learning in knowledge acquisition for competitive advantage is increasingly found in the literature. Various researchers have used qualitative, single firm case studies to validate a relationship between learning, knowledge and firms exhibiting strong market performance. There is, however, limited empirical evidence on the relative importance of the learning style and management systems required to support the effective marketing of knowledge-based services. The Internet is an excellent research tool to empirically assess the possible relationships between learning style, knowledge systems and revisions in operational practices. A survey of small UK accountancy practices was undertaken to acquire data on learning style, knowledge systems and market performance. The results and their implications in relation to organisations' use of the Internet are discussed and proposals are presented for further research.

Notes: Organisational learning is increasingly being mentioned in the literature as a mechanism for assisting the market performance of small firms. There exists, however, limited empirical evidence on either the benefits conferred by organisational learning and the learning systems utilised to manage the process. A survey of small UK manufacturing firms was undertaken to acquire data on whether a relationship exists between learning style and the competencies exhibited by organisations. The survey also sought to determine the nature of learning systems used by small manufacturing firms. The results suggest that as firms move from a lower-level to a higher-level learning style, this is accompanied by competence enhancement that can contribute to improving organisational capability. It also appears that a higher-level learning style is accompanied by the adoption of a more formalised learning system inside the organisation. The implications of these findings are discussed and proposals presented on the needs for further research.

Notes: The results from a survey for proliferative kidney disease (PKD) and renal myxosporidiosis in wild salmonids from rivers in England and Wales are presented. One hundred and eighty-five salmon, Salmo salar, 235 brown trout, Salmo trutta, 16 charr, Salvelinus alpinus, and five grayling, Thymallus thymallus, were obtained from 23 locations on 16 rivers between July and October 1997. They were examined for the presence of clinical PKD and for histological evidence of infections with Tetracapsula bryosalmonae and other renal myxozoans. Prevalence of infection with T. bryosalmonae detected histologically in brown trout varied from 11 to 43% in enzootic rivers and was only found in salmon in two rivers at low prevalence. Nephromegaly was positively associated with PKD in brown trout but in salmon mild nephromegaly was only associated with infection with an unidentified Chloromyxum sp.

Notes: [Auszug] Hirschsprung disease (HSCR) is a multigenic, congenital disorder that affects 1 in 5,000 newborns and is characterized by the absence of neural crest–derived enteric ganglia in the colon. One of the primary genes affected in HSCR encodes the G protein–coupled endothelin receptor-B ...

Notes: In the literature, relationship orientated firms are being advised to exploit organizational learning as a route through which to acquire the knowledge required to survive in rapidly changing and/or highly competitive markets. There is, however, only limited anecdotal evidence of the positive contribution that organizational learning can make to enhancing the performance of firms. To acquire additional empirical data, a survey of learning style and perception of competences relative to competitors in small manufacturing firms was undertaken. Results concerning organizational learning style appear to indicate the firms who exhibit a relationship marketing style tend to adopt a double-loop (or table8.TIFigher order) learning style; whereas transactionally orientated firms appear to be single-loop learners. When compared with transactional firms, relationship orientated respondents also reported higher competences for some areas of marketing, HRM and information management practices. This conclusion was further validated through telephone interviews. The implications of these findings are discussed and proposals presented on the need for further research.

Notes: Abstract. It is shown that if K is a compact convex set which is centrally symmetric and has a nonempty interior, then the density of the tightest lattice packing with copies of K in Euclidean 3-space divided by the density of the thinnest lattice covering of Euclidean 3-space with copies of K is greater than or equal to 1/4. It is likely this bound can be improved, though not beyond approximately 1/2.