Book Reviews

Book Review 1Book Title: Social Behaviour in AnimalsBook Author: N. TinbergenChapman & Hall, London, 1988.Book Review 2Book Title: Plankton Ecology. Succession in plankton communitiesBook Author: Edited by U. SommerSpringer-Verlag, New York, 1989. x + 369 pages.Book Review 3Book Title: Intrazooplankton PredationBook Authors: Edited by H.J. Dumont, J.G. Tundisi & K. RocheKluwer Academic Publishers, Dordrecht, 1990. 242 pages

A baseline limnological study of Wagendrift Dam (Thukela basin, KwaZulu-Natal)

Basic features of the physical and biological limnology of Wagendrift Dam, a moderately large impoundment on the Boesmans River, were studied between July 1989 and May 1990. This man-made lake showed a typical monomictic pattern of summer stratification (November through April) and holomictic winter circulation (May to October). Water quality was chemically good (Department of Water Affairs and Forestry records), with little evidence of nutrient enrichment. Water clarity during the study was moderately low (mean SD and K d PAR values of 0.45 m and 2.55 m-1), with little evidence of persistent mineral turbidity, suggesting reasonably satisfactory catchment conditions. In keeping with the low nutrient status, surface chlorophyll content remained below 5 ?g ·l -1 throughout the study. In terms of ecological groupings, the phytoplankton was numerically dominated mostly by 'Competitive' green algae for most of the year. 'Stress-tolerant' cyanophytes were continuously sparse, but were marginally more abundant during summer stratification. Diatoms and other disturbance-tolerant 'ruderal' algae persisted throughout the year. No spring peak in ruderal algae was evident, but it may have been masked by high zooplankton grazing pressure. An autumnal peak in ruderal algae coincided broadly with flood-related inflows and annual de-stratification. Zooplankton was dominated (numerically and/or gravimetrically) by typical clear-water taxa. The copepod Tropodiaptomus spectabilis and cladoceran Daphnia pulex along with various unidentified cyclopoids and rotifers were seasonally persistent, while other cladoceran taxa (D. laevis and Diaphanosoma excisum) showed considerable seasonal periodicity. Zooplankton standing stock was collectively substantial, annually averaging around 0.65 g·m -2 DM, and approaching 1 g·m -2 DM in spring/early summer, implying potentially significant natural grazer-control of phytoplankton, aided perhaps by large numbers of benthic bivalve molluscs (Unio caffer), observed stranded in littoral margins following reservoir draw-down. WaterSA Vol.27(4) 2001: 507-51

Thatcher’s Britain: : a new take on an old illusion

The Thatcher Illusion is generally discussed as a phenomenon related to face perception. Nonetheless, we show that compellingly strong Thatcher Effects can be elicited with nonface stimuli, provided that the stimulus set has a familiar standard configuration and a canonical view. Apparently, the Thatcher Illusion is not about faces, and nor is it about Thatcher. It just might, however, be about Britain

Host Determinant Residue Lysine 627 Lies on the Surface of a Discrete, Folded Domain of Influenza Virus Polymerase PB2 Subunit

Understanding how avian influenza viruses adapt to human hosts is critical for the monitoring and prevention of future pandemics. Host specificity is determined by multiple sites in different viral proteins, and mutation of only a limited number of these sites can lead to inter-species transmission. Several of these sites have been identified in the viral polymerase, the best characterised being position 627 in the PB2 subunit. Efficient viral replication at the relatively low temperature of the human respiratory tract requires lysine 627 rather than the glutamic acid variant found systematically in avian viruses. However, the molecular mechanism by which any of these host specific sites determine host range are unknown, although adaptation to host factors is frequently evoked. We used ESPRIT, a library screening method, to identify a new PB2 domain that contains a high density of putative host specific sites, including residue 627. The X-ray structure of this domain (denoted the 627-domain) exhibits a novel fold with the side-chain of Lys627 solvent exposed. The structure of the K627E mutated domain shows no structural differences but the charge reversal disrupts a striking basic patch on the domain surface. Five other recently proposed host determining sites of PB2 are also located on the 627-domain surface. The structure of the complete C-terminal region of PB2 comprising the 627-domain and the previously identified NLS-domain, which binds the host nuclear import factor importin alpha, was also determined. The two domains are found to pack together with a largely hydrophilic interface. These data enable a three-dimensional mapping of approximately half of PB2 sites implicated in cross-species transfer onto a single structural unit. Their surface location is consistent with roles in interactions with other viral proteins or host factors. The identification and structural characterization of these well-defined PB2 domains will help design experiments to elucidate the effects of mutations on polymerase–host factor interactions

Wind turbine main-bearing lubrication - part 1 : an introductory review of elastohydrodynamic lubrication theory

This paper is the first in a two-part study on lubrication in wind turbine main-bearings. Elastohydrodynamic lubrication is a complex field, the formulas and results from which should not be applied blindly, but with proper awareness and consideration of their context, validity and limitations in any given case. The current paper, “Part 1”, therefore presents an introductory review of elastohydrodynamic lubrication theory in order to provide this necessary background and context in an accessible form, promoting cross-disciplinary understanding. Fundamental concepts, derivations and formulas are presented, followed by the more advanced topics of: starvation, dynamic effects, surface roughness interactions and grease lubrication. “Part 2” applies the presented material in order to analyse wind turbine main-bearing lubrication in the context of available film thickness formulas and related results from lubrication theory. Aside from the main-bearing, the material presented here is also applicable to other lubricated non-conformal contacts in wind turbines, including pitch and yaw bearings and gear-teeth

Evaluation and learning from failure and success: An ANZSOG research paper for the Australian Public Service Review Panel

A research report of how accountability mechanisms within the APS can be improved to ensure evidence-based policy making and advice to government. The authors contend the APS must change how it evaluates the outcomes of its programs and how it learns from examples of success (as well as failure) to ensure more effective and efficient public sector management.Commissioned by Independent Review of the Australian Public Service, ANZSOG