Book reviews

COMMUNITY PARTICIPATION: A Practical Guide. Wendy Sarkissian, Andrea Cook & Kelvin Walsh. Institute for Science and Technology. Murdoch University, Murdoch, WA, June 1997. ISBN 0 86905 556 9. 242pp, RRP $35.00, Spiral Bound.

GENDER, WORK AND SPACE. Susan Hanson and Geraldine Pratt. Routledge, New York, 1995. 272 pp, $90 Hardback. ISBN 0-415-09940-4 (hbk); 0-415-09941-2(pbk).

SUSTAINABILITY, THE ENVIRONMENT AND URBANISATION. Cedric Pugh (Ed). Earthscan Publications Ltd, London, 1996. ISBN 1 85383 357 6. 250 pp, cost unknown, paperback.

RATIONALITY & POWER: Democracy in Practice. Bent Flyvbjerg (transl. S. Sampson). The University of Chicago Press, Chicago, 1998. ISBN 0 226 25451 6 (pbk). 290pp, incl. notes, bibli. & index. US$16.95 (app. A$30).

TOWARDS COSMOPOLIS. Leonie Sandercock. Chichester, John Wiley & Sons, 1998, 258pp.     

Socio-economic pitfalls of enhancing indigenous capabilities in household fermentation

Traditional fermentation processes are increasingly attracting the attention of scientists and policy makers as a vital part of food security strategies. New opportunities provided by biotechnology are opening up possibilities to improve or upgrade traditional small-scale processes and make better use of agricultural products. A straightforward transfer-of-technology approach, characteristic for mainstream development assistance to developing countries, is inappropriate to upgrade and improve the traditional food processing sector in developing countries. In this paper, the case of soy sauce fermentation in Indonesia is presented to illustrate the dangers of narrowing traditional food processing to a sequence of operations. These processes and their operations reflect the social, political, cultural and ethnical relations in which they emerged and evolved. Successful upgrading requires that these relations are understood and that, based on such an understanding, modern technologies build upon their traditional predecessors. Any technology or project that neglects the coherence between these relations or is unable to meet social, political and cultural requirements in addition to technical ones, is doomed to fail.     

Solid-phase microextraction to predict bioavailability and accumulation of organic micropollutants in terrestrial organisms after exposure to a field-contaminated soil

The risk posed by soil contaminants strongly depends on their bioavailability. In this study, a partition-based sampling method was applied as a tool to estimate bioavailability in soil. The accumulation of organic micropollutants was measured in two earthworm species (Eisenia andrei and Aporrectodea caliginosa) and in 30-microm poly(dimethylsiloxane) (PDMS)-coated solid-phase micro extraction (SPME) fibers after exposure to two field-contaminated soils. Within 10 days, steady state in earthworms was reached, and within 20 days in the SPME fibers. Steady-state concentrations in both earthworm species were linearly related to concentrations in fibers over a 10,000-fold range of concentrations. Measured concentrations in earthworms were compared to levels calculated via equilibrium partitioning theory and total concentrations of contaminants in soil. In addition, freely dissolved concentrations of contaminants in pore water, derived from SPME measurements, were used to calculate concentrations in earthworms. Measured concentrations in earthworms were close to estimated concentrations from the SPME fiber measurements. Freely dissolved concentrations of contaminants in pore water, derived from SPME measurements, were used to calculate bioconcentration factors (BCF) in earthworms. A plot of log BCFs against the octanol-water partition coefficient (log Kow) was linear up to a log Kow of 8. These results show that measuring concentrations of hydrophobic chemicals in a PDMS-coated fiber represents a simple tool to estimate internal concentrations of chemicals in biota exposed to soil.     

Physical properties of tempered mixtures of cocoa butter,CBR and CBS fats

Physical characteristics of precrystallised binary mixtures of cocoa butter (CB) and 5, 10, 15, 20, 25 and 30% (w/w) cocoa butter replacer (CBR) or cocoa butter substitute (CBS) were determined. The lipid composition was obtained by chromatography and the solid fat content (SFC) by nuclear magnetic resonance. Tempering was carried out using a lab‐scale agitated jacket vessel reactor. Bars made with tempered samples were submitted to X‐ray diffraction and rupture tests. Snap values of crystallised mixtures decrease with an increase in the amount of alternative fat. X‐ray diffraction patterns confirmed the predominant formation of the beta polymorph habit for CB and beta prime form for CBR and CBS. Mixtures of CB and CBR exhibit chemical compatibility. The knowledge of the snap values and of the variation of SFC with temperature proved to suffice to adequately anticipate the influence of the addition of alternative fats on chocolates physical attributes.     

Dynamics of intramammary infections in suckler ewes during early lactation

Mastitis is an important problem in meat-producing sheep, but few studies have investigated the transmission dynamics of mastitis pathogens in these animals. The objective of this study was to describe the pathogens causing intramammary infections (IMI) in suckler ewes, their effect on somatic cell count, and the dynamics of these IMI in early lactation. We enrolled 15 sheep flocks early after lambing and selected ewes in each flock that were sampled twice with a 3-wk interval. Milk samples from both glands of each ewe were bacteriologically cultured, and somatic cell count was measured. Non-aureus Staphylococcus spp. were the most prevalent culture results. Somatic cell counts were most strongly increased in ewes infected with Mannheimia haemolytica, whereas staphylococci, including Staphylococcus aureus, were associated with a moderate increase in somatic cell count. The proportion of udder halves that remained culture-positive with Staphylococcus spp. during the 3-wk sampling interval was moderate, but M. haemolytica infections were stable during this time period. A substantial number of new infections were seen in the early lactation study period for non-aureus Staphylococcus spp., Staph. aureus, and Corynebacterium spp., but not for M. haemolytica or Streptococcus spp. The number of new IMI of Staph. aureus was associated with the number of Staph. aureus-infected udder halves in the flock at the first sampling moment, indicative of contagious transmission. Altogether, we show that substantial transmission happens in early lactation in suckler ewes, but that the dynamics differ between pathogen species. More research is needed to further describe transmission in different stages of lactation and to identify transmission routes, to develop effective interventions to control mastitis.     

Natamycin release from alginate/pectin films for food packaging applications

Single and composite films based on alginate and pectin containing natamycin as active agent were prepared and the release behavior in water and the diffusion coefficients were evaluated. The influence of natamycin on physical attributes of the films was also investigated. Addition of natamycin promoted an increase in soluble matter in water, in the water vapor permeability and in the opacity and a decreased in tensile strength when compared to films without the added anti-microbial agent. The natamycin mass released by immersion of the film in water fitted well to Fick’s second law diffusional model, with effective diffusivity values ranging from 3.2 × 10⁻⁹ (single pectin films) to 9.2 × 10⁻¹² cm²/s (single alginate films). The values of the diffusional exponents ranged between 0.5 and 1.0, suggesting that the transport process had non-Fickian (anomalous) characteristics. The single alginate films exhibit more suitable attributes for application in packaging than the single pectin and the composite films.     

Same-sex attraction, social relationships, psychosocial functioning, and school performance in early adolescence.

The authors examined whether 13- to 15-year-old adolescents who experience feelings of same-sex attraction (SSA) differ from those without such feelings in the quality of relationships with parents, peers, and class mentors and in psychosocial functioning (health status and school performance). The authors also assessed whether differences in psychosocial functioning resulted from differences in the quality of social relationships. Data were collected from 866 Dutch high school students (mean age 13.61 years) by means of a computer-based questionnaire. Of the participants, 74 (8.5%) reported having feelings of SSA. The participants with SSA rated the quality of their relationships with their fathers and their peers lower than did those without SSA. Participants with SSA also had poorer mental health (higher levels of depression and lower levels of self-esteem) and lower school performance. A mediation analysis revealed that differences in psychosocial functioning resulted from differences in the quality of the same-sex attracted youths' social relationships, especially with fathers and peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modelling and Closed‐loop Control of Complex Tube Forming Based on an Optimized Application of Martensite Formation in Austenitic Stainless Steels

Metastable austenitic steels undergo deformation‐induced martensitic transformation which can lead to a distinct increase of fatigue strength at an optimal volume fraction of martensite. This effect was used in the present study to define the local strength behaviour of a structural component part for the very high cycle fatigue (VHCF) regime. The investigation was on a discontinuous two‐stage forming process that consists of U‐O‐forming and rotary draw bending and results in a cross tube of a trailer coupling as exemplary dynamically loaded component. The volume fraction of martensite can be adjusted by means of plastomechanical simulation of the forming process and its parameters as part of the online process control. The formation of martensite shows a strong dependence on forming parameters (e.g. temperature and strain‐rate) and batch variations. These disturbance variables can only be taken into account by a closed‐loop control. Non‐isothermal material models were analysed according to their simulation accuracy of the martensite evolution. For the online control various hierarchical mathematical models were studied with regard to time effort and model error.