The Genus Wolbachia

Numerous invertebrate species form long lasting symbioses with bacteria (Buchner, 1949; Buchner, 1965). One of the most common of these bacterial symbionts is Wolbachia pipientis, which has been estimated to infect anywhere from 15–75% of all insect species (Werren et al., 1995a; West et al., 1998; Jeyaprakash and Hoy, 2000; Werren and Windsor, 2000) as well as many species of arachnids, terrestrial crustaceans and filarial nematodes (O’Neill et al., 1997a; Bandi et al., 1998). In most arthropod associations, Wolbachia act as reproductive parasites manipulating the reproduction of their hosts to enhance their own vertical transmission. There appears to be little direct fitness cost to the infected host besides the costs arising from the reproductive manipulations. However instances have been reported where Wolbachia can be either deleterious (Min and Benzer, 1997; Bouchon et al., 1998) or beneficial (Girin and Boultreau, 1995; Stolk and Stouthamer, 1995; Wade and Chang, 1995; Vavre et al., 1999b; Dedeine et al., 2001) to their hosts. Wolbachia were first described as intracellular Rickettsia-like organisms (RLOs), infecting the gonad cells of the mosquito, Culex pipiens (Hertig and Wolbach, 1924), and were later named 'Wolbachia pipientis' (Hertig, 1936). It was not until the work of Yen and Barr (Yen and Barr, 1971; Yen and Barr, 1973) that Wolbachia were implicated in causing crossing incompatibilities between different mosquito populations (Laven, 1951; Ghelelovitch, 1952). When polymerase chain reaction (PCR) diagnostics for Wolbachia became available, it became clear that this agent was both extremely widespread and also responsible for a range of different reproductive phenotypes in the different hosts it infected (O’Neill et al., 1992; Rousset et al., 1992; Stouthamer et al., 1993). The most common of these are cytoplasmic incompatibility, inducing parthenogenesis, overriding host sex-determination, and male-killing (O’Neill et al., 1997a). As of the time of this writing, more than 450 different Wolbachia strains with unique gene sequences, different phenotypes, and infecting different hosts have been deposited in GenBank and the Wolbachia host database (http://www.wolbachia.sols. uq.edu.au).

The current status of psychological debriefing - It may do more harm than good

Despite the widespread use of psychological debriefing, serious concerns have been raised about its effectiveness and potential to do harm. 1 2 Psychological debriefing is broadly defined as a set of procedures including counselling and the giving of information aimed at preventing psychological morbidity and aiding recovery after a traumatic event. In 1995 Raphael and colleagues emphasised that there was an urgent need for reliable evidence from randomised controlled trials on the impact and worth of debriefing.3 Unfortunately, the news has not been good for debriefing. Debriefing is generally applied within the first few days after a traumatic event, lasts one to three hours, and usually includes procedures that encourage and normalise emotional expression. Debriefing can also be more narrowly defined in terms of the procedures used, the information provided and the target population. One example of this type of debriefing is known as critical incident stress debriefing.4

Cervical screening in migrants to Australia

Objective: To examine differentials and time trends in self-reported Pap test rates by migrant status from the 1989/90 and 1995 Australian National Health Surveys (NHS). Method: Unit record data for females with the variables of interest were extracted from the 1989/90 and 1995 NHS and combined. The dichotomous outcome variables were 'ever had a Pap test and 'had a Pap test within three years'. The principal study factor was country-of-birth, but language spoken at home (English or not) was also examined. The indirect age-standardised screening ratio was used to calculate proportions of 'ever had a Pap test' and 'had a Pap test within three years' and differences were tested statistically using logistic regression analysis for each year of survey by migrant status. Results: Odds ratios for rates of reporting 'ever had a Pap test' were significantly lower in women born in southern Europe, Italy, other countries, southern Asia, Middle East, Greece and South-East Asia compared with Australian-born. Reported rates of 'ever had a Pap test' were significantly higher in the 1995 NHS (p

Computational immunology: The coming of age

The explosive growth in biotechnology combined with major advancesin information technology has the potential to radically transformimmunology in the postgenomics era. Not only do we now have readyaccess to vast quantities of existing data, but new data with relevanceto immunology are being accumulated at an exponential rate. Resourcesfor computational immunology include biological databases and methodsfor data extraction, comparison, analysis and interpretation. Publiclyaccessible biological databases of relevance to immunologists numberin the hundreds and are growing daily. The ability to efficientlyextract and analyse information from these databases is vital forefficient immunology research. Most importantly, a new generationof computational immunology tools enables modelling of peptide transportby the transporter associated with antigen processing (TAP), modellingof antibody binding sites, identification of allergenic motifs andmodelling of T-cell receptor serial triggering.

Modelling of Lamb waves in composite laminated plates excited by interdigital transducers

The technique of permanently attaching interdigital transducers (IDT) to either flat or curved structural surfaces to excite single Lamb wave mode has demonstrated great potential for quantitative non-destructive evaluation and smart materials design, In this paper, the acoustic wave field in a composite laminated plate excited by an IDT is investigated. On the basis of discrete layer theory and a multiple integral transform method, an analytical-numerical approach is developed to evaluate the surface velocity response of the plate due to the IDTs excitation. In this approach, the frequency spectrum and wave number spectrum of the output of IDT are obtained directly. The corresponding time domain results are calculated by applying a standard inverse fast Fourier transformation technique. Numerical examples are presented to validate the developed method and show the ability of mode selection and isolation. A new effective way of transfer function estimation and interpretation is presented by considering the input wave number spectrum in addition to the commonly used input frequency spectrum. The new approach enables the simple physical evaluation of the influences of IDT geometrical features such as electrode finger widths and overall dimension and excitation signal properties on the input-output characteristics of IDT. Finally, considering the convenience of Mindlin plate wave theory in numerical computations as well as theoretical analysis, the validity is examined of using this approximate theory to design IDT for the excitation of the first and second anti-symmetric Lamb modes. (C) 2002 Elsevier Science Ltd. All rights reserved.

Yehoshua Gitay: 'What is He Doing?'

This article provides a response to an article by Yehoshua Gitay, ‘Prophetic Criticism—"What are they Doing?": The Case of Isaiah—A Methodological Assessment’ (JSOT 96), in which he assesses the articles in the volume, New Visions of Isaiah. These articles were originally delivered as papers to the Formation of the Book of Isaiah Seminar of the Society of Biblical Literature. Gitay characterizes the entire work of the Seminar as having a redaction-critical focus. I argue that to characterize my article as representing a redaction-critical approach is to misunderstand what others and I were doing as participants in the Isaiah seminar. My article was in fact a critique of redaction criticism and its author-centred approach to textual meaning.