Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event.

The Galactic Centre contains a supermassive black hole with a mass of four million Suns1 within an environment that differs markedly from that of the Galactic disk. Although the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings2. Also, although the levels of star formation in the Galactic Centre have been approximately constant over the past few hundred million years, there is evidence of increased short-duration bursts3, strongly influenced by the interaction of the black hole with the enhanced gas density present within the ring-like central molecular zone4 at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200-parsec region is characterized by large amounts of warm molecular gas5, a high cosmic-ray ionization rate6, unusual gas chemistry, enhanced synchrotron emission7,8, and a multitude of radio-emitting magnetized filaments9, the origin of which has not been established. Here we report radio imaging that reveals a bipolar bubble structure, with an overall span of 1 degree by 3 degrees (140 parsecs × 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 × 1052 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities.

Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.

Genotyping with real-time PCR reveals recessive epistasis between independent QTL conferring resistance to common bacterial blight in dry bean.

Resistance to common bacterial blight in common bean is a complex trait that is quantitatively inherited. Combining QTL is the current strategy for improving resistance, but interactions among different QTL are unknown. We examined the interaction between two independent QTL present in dry bean breeding line XAN 159. The QTL were studied in a near isogenic population consisting of 120 BC6:F2 plants. Each BC6:F2 plant was evaluated for disease reaction at several time points after pathogen inoculation and the dominant SCAR markers linked with QTL on linkage groups B6 (BC420 approximately QTL) and B8 (SU91 approximately QTL) were interpreted as codominant markers using real time PCR assays. This enabled assignment of BC6:F2 plants to all nine possible genotypes. Reaction to CBB in BC6:F2 plants was characterized by an epistatic interaction between BC420 and SU91 such that: 1) the expression of BC420 was epistatically suppressed by a homozygous recessive su91//su91 genotype; 2) SU91//SU91 and SU91//su91 genotypes conditioned an intermediate disease reaction when homozygous recessive for bc420//bc420; and 3) the highest level of disease resistance was conferred by genotypes with at least a single resistance allele at both QTL (BC420//-; SU91//-). Segregation for resistance among BC6:F3 plants derived from BC6:F2 plants that were heterozygous for both QTL did not deviate significantly from expected ratios of 9 resistant: 3 moderately resistant: 4 susceptible. This is consistent with a recessive epistatic model of inheritance between two loci. These results indicate breeders will realize greatest gains in resistance to CBB by selecting breeding materials that are fixed for both QTL. This is a first report of a qualitative digenic model of inheritance discerning an interaction between two QTL conditioning disease resistance in plants.

Treating Phobias or Treating People ? Of Acronyms and the Social Context

Phobias are some of the most common disorders brought to the attention of treatment agents. Classically; the treatment of choice was SD (systematic desensitisation); sometimes combined with hypnosis. More recently; VR (virtual reality) procedures and EMDR (eye movement desensitisation reprocessing) emerged as exciting alternatives. SD and the VR procedures are operationalisations of CBT (cognitive behaviour therapy) and are based on learning theory; while EMDR is usually viewed from a psychoneurological perspective. The generally good results obtained with the methods known by these acronyms are often taken to confirm the soundness of the particular underlying theory. However; these theories under-represent the interpersonal or social aspects of phobic behaviour. Adding an inter-personal focus to the generally intra-personal view of this behaviour much more fully explains both the success of the usual treatment procedures and the relatively rare failures. Using case illustrations; this paper highlights the way in which phobic behaviour is often embedded in a matrix of interpersonal and social influences and suggests the more deliberate and effective utilisation of these in the treatment of phobic sufferers

Occurrence of Bacterial Brown Spot on Dry Beans in Zimbabwe.

A previously unreported leaf spot disease was observed in dry bean variety trials in Harare, Zimbabwe, during March 2000. It was subsequently noticed on the cultivars Ex-Rico and C20 in commercial fields. The irregular, brown, necrotic lesions (0.5 to 5 mm in diameter) resembled typical symptoms of bacterial brown spot. A fluorescent bacterium was isolated from diseased leaf samples on King's B medium. LOPAT tests (2) classified the bacterium as a Group 1a fluorescent plant pathogenic pseudomonad. Agglutination with a specific antibody reagent, from the Adgen Express test kit, positively identified the bacterium as Pseudomonas syringae pv. syringae, the causal organism of bacterial brown spot. The pathogen was distinguished from P. syringae pv. phaseoli, the halo blight organism, by its ability to utilize mannitol, inositol, and sorbitol and its ability to grow on KBC medium (3). The utilization of sucrose as a sole carbon source distinguished the pathogen from P. viridiflava. Pathogenicity of isolates was verified by inoculating young attached pods of the cultivar Teebus, using the method of Cheng et al. (1). Control plants were inoculated with a sterile syringe needle dipped in sterile distilled water. Inoculated plants were maintained in a greenhouse at 28°C day/18°C night for 4 days before being evaluated for symptom development. P. syringae pv. syringae was consistently recovered from typical lesions that developed on inoculated pods. No symptoms developed on control pods. This is the first report of bacterial brown spot caused by P. syringae pv. syringae on dry beans in Zimbabwe. P. syringae pv. syringae was, however, isolated in South Africa from extracts of bean seed received from Zimbabwe in 1996, although it is uncertain whether the disease actually occurred in the field during that specific season. References: (1) G. Y. Cheng et al. Plant Dis. 73:419, 1989. (2) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (3) S. K. Mohan and N. W. Schaad. Phytopathology 77:1390, 1987.

Confirming false memories: social construction of "useful" meanings.

Data from a recent case study is presented to illustrate how false memories are socially constructed in the present and how they fulfill a function for the system in which such construction takes place. Based on the dubious assumption that hypnotic age-regression brings forth the historical "truth" about past events, hypnosis was misused as part of this construction, even while the outcome of the regression had to be distorted to provide confirmation of the particular memory.

Characterization of Halo Blight Races on Dry Beans in South Africa.

Isolates of the halo blight pathogen Pseudomonas syringae pv. phaseolicola were collected in the bean-producing areas in South Africa from 1991 to 1996. Of the 1,128 isolates collected, 967 were identified as P. syringae pv. phaseolicola. The majority of these isolates were obtained from a wide range of Phaseolus vulgaris cultivars, and the rest from P. coccineus and P. lunatus. Two hundred fifty-five isolates, representative of all the localities and cultivars sampled, were categorized into different races according to their reaction on a set of differential cultivars. Seven races (1, 2, 4, 6, 7, 8, and 9) were identified, with race 8 the most prevalent. Races 1, 2, 6, and 8 were widely distributed through the whole production area, while races 4, 7, and 9 were restricted to one or two localities.

"Indirect" suggestion in hypnosis: theoretical and experimental issues.

"Indirect" suggestion is conceptualized in two distinct ways in the literature. From an Ericksonian perspective "indirect" suggestions are theoretically approached as suggestions which can circumvent the censorship of consciousness to reach the "unconscious" where they can activate dormant potentials. In contrast, from a research perspective "indirect" suggestion is operationally defined as a technique. Based on Ericksonian theory, it was claimed that "indirect" suggestion was more effective than traditional, "direct" suggestion. However, this claim could not be empirically substantiated. In this paper it is shown that the theoretical claim is based on questionable assumptions about the existence of the "unconscious" as a reified entity and about the direct and lineal influence of certain suggestions on this entity. Also, it is argued that traditional research strategies which emphasize strict controls are unable to verify or unambiguously refute the Ericksonian claim because these strategies are biased toward "direct" suggestion. Finally, the paper provides a different, contextual perspective on "indirect" suggestion, thereby placing the theoretical and experimental issues in a different context of meaning.

Chondrodysplasia punctata: case report and literature review of patients with heart lesions.

Chondrodysplasia punctata (CP) is sometimes accompanied by heart lesions, but the literature is not specific or consistent regarding the incidence or types of cardiac anomalies. A patient with the mild Conradi-Hünermann type of CP is peripheral pulmonary arterial stenoses. A review of the literature brought to light a total of 23 patients with congenital heart lesions that were mainly found among cases of Conradi-Hünermann type and autosomal recessively inherited CP.

Attribution of meaning: an ecosystemic perspective on hypnotherapy.

Although the concept of attribution of meaning has been used previously in theorizing about hypnosis, it was in the development of an ecosystemic conceptualization of hypnosis that it came to the fore as of major practical importance. The way clients and families think about themselves, about their problems, and about hypnosis has particular implications for hypnotherapy. In this paper a theoretical rationale for the development of the concept of attribution of meaning is provided. It is also shown, by means of case examples, how emphasis on the attributions made by clients can influence the manner in which particular hypnotherapeutic strategies are employed.

From Erickson to attribution: attaching meaning to hypnosis.

On the surface it seems that various Ericksonian theories of hypnotherapy differ considerably from each other; however, they can all be seen to be similar in three areas, namely, focus on the intrapsychic activities of the individual, focus on linear causality, and focus on objectivity of observation. These three foci are shown to embody certain conceptual and practical limitations. It is suggested that such limitations may be circumvented if Ericksonian techniques are applied from the perspective of attribution of meaning rather than from the point of view of reductionism, linearity, and objectivity.

Simulation in hypnosis research: the "hidden" role of attribution of meaning.

The role played by attribution of meaning in research involving simulation is examined. Acknowledgement of this role, lacking to date, queries the traditional use of simulation but also opens up interesting research questions.

Smodingium dermatitis.

Smodingium argutum is the plant most commonly responsible for causing acute allergic contact dermatitis in South Africa. When an outbreak of Smodingium dermatitis occurred in a local school the allergenic principle present in this plant was chemically isolated and identified, and its allergenic property proved in the clinic by patch testing. The value of using an extract of fresh Smodingium leaves in lieu of fresh leaves themselves was confirmed, but freeze-dried material was found to be unsuitable for patch-test purposes.

Some aspects of tetanus neonatorum in the Pretoria area.

Thirty-four cases of tetanus neonatorum seen over a period of 2 years are analysed as regards severity, place and mode of birth of the affected infant and level of antenatal care. Possible methods of prevention are discussed in the light of the findings.

Relationship aspects of hypnotic susceptibility.

If hypnosis is seen from an interpersonal point of view it could be hypothesized that aspects of the relationship existing between the hypnotist and the subject prior to hypnosis would probably be related to the subject's susceptibility to the hypnosis. A study was conducted to test this hypothesis. 19 volunteer subjects were individually tested for hypnotic susceptibility using the Stanford Hypnotic Susceptibility Scales, Form A. In each case this was preceded by a short tape-recorded non-directive interview. Four independent raters rated the interviews on 10 behavioral dimensions plus general "hypnotizability," using seven-point scales. Although the coefficients of interrater agreement were generally low, the signs of the correlations between mean ratings and Stanford scores were as predicted in all 11 cases. Three of the correlations were significant. From a principal components analysis on the intercorrelation matrix, three factors emerged of which one was labelled Hypnotic Susceptibility.