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A letter to the editor is presented in response to the article "Perfusion and diffusion magnetic resonance imaging in idiopathic intracranial hypertension," published in the previous issue of the periodical.

To evaluate the impact of European Society of Endodontology curriculum guidelines on undergraduate teaching in the UK.A postal questionnaire was designed by two authors (WPS, GB) in 2003. This included open and closed questions relating to endodontic curricula and the impact of curriculum guidelines. This was sent with a cover letter to the thirteen UK undergraduate schools. Data harvest was completed a year after the initial questionnaires were sent. Responses were collated and analysed qualitatively and quantitatively.Eight (62%) questionnaires were returned. Analysis revealed divergence from aspects of curriculum guidelines. Guidelines were applied by seven schools. Four schools had not applied guidelines related to endodontic surgery as this was taught by Departments of Oral Surgery. One respondent stated that the established curriculum was too inflexible to allow application. There was wide variation in curriculum structure with combinations of outcome, competency and problem-based learning. No schools had a separate department of Endodontology. All schools felt graduates should be competent at de-novo treatment of single and multi-rooted teeth. In general, competence was expected in single canal re-treatment but not multi-rooted teeth. Patient recruitment proved a major barrier to meeting guidelines. Number of cases to be completed by graduation ranged from 6 to 14 in total. Three schools felt that guidelines were not achievable citing lack of time, funds and appropriate staff.All schools provided operative techniques classes prior to clinical treatment. These ranged from 20 to 120 hours (mean 43, S.D. 35.24.). Cases completed in these classes varied. For single rooted teeth this ranged from one to six (mean 2.57). For multi-rooted teeth this ranged from one to three (mean 2.14). Most schools had at least one faculty member with a special interest in Endodontology. In seven schools however, teaching was also carried out by staff with no special interest. Five schools did not have a separate endodontic clinic. Five respondents had undergraduate learning in outreach centres. Trauma teaching was mainly carried out by in Departments of Paediatric Dentistry.There is wide variation in the delivery of endodontic curricula in the U.K. Whilst curriculum guidelines are available, there are barriers to delivering these. Consideration should be given to revision of guidelines in light of their evident inapplicability in some areas. [ABSTRACT FROM AUTHOR]

The Tokamak simulation code (TSC) is used to provide initial conditions for predictive TRANSPort and integrated modeling code (PTRANSP) simulations of ITER target steady state scenarios. The PTRANSP simulations are carried out using the new multi-mode (MMM7.1) and the gyro-Landau-fluid (GLF23) transport models. It is found that there are circumstances under which the total fusion power decreases with increasing pedestal temperature height. When the total current (from magnetic axis to plasma edge) is fixed, an increased fraction of the current is concentrated in the pedestal region as the pedestal height is increased. As a consequence of the fixed total current, this results a smaller fraction of the current in the core plasma and, consequently, lower energy confinement. In previous simulations of ITER, in which the fusion power increased with increasing pedestal temperature height, the plasma current from the top of the pedestal to the magnetic axis was held fixed independent of the pedestal temperature. Simulations presented in this paper also indicate that improvement in fusion power production occurs when the lower hybrid current drive is replaced with electron cyclotron current drive. Again, the improvement results from the redistribution of plasma current since the lower hybrid power generally drives current closer to the plasma edge than does the electron cyclotron power. ITER simulation results obtained using the MMM7.1 transport model are compared with those using the GLF23 model. It is found that, in simulations of target steady state scenarios, momentum transport and flow-shear suppression features of the new MMM7.1 model can lead to predictions of internal transport barriers in temperature and rotation frequency. [ABSTRACT FROM AUTHOR]

Electron thermal transport in DIII-D H-mode tokamak plasmas [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated by comparing predictive simulation results for the evolution of electron temperature profiles with experimental data. The comparison includes the entire profile from the magnetic axis to the bottom of the pedestal. In the simulations, carried out using the automated system for transport analysis (ASTRA) integrated modeling code, different combinations of electron thermal transport models are considered. The combinations include models for electron temperature gradient (ETG) anomalous transport and trapped electron mode (TEM) anomalous transport, as well as a model for paleoclassical transport [J. D. Callen, Nucl. Fusion 45, 1120 (2005)]. It is found that the electromagnetic limit of the Horton ETG model [W. Horton et al., Phys. Fluids 31, 2971 (1988)] provides an important contribution near the magnetic axis, which is a region where the ETG mode in the GLF23 model [R. E. Waltz et al., Phys. Plasmas 4, 2482 (1997)] is below threshold. In simulations of DIII-D discharges, the observed shape of the H-mode edge pedestal is produced when transport associated with the TEM component of the GLF23 model is suppressed and transport given by the paleoclassical model is included. In a study involving 15 DIII-D H-mode discharges, it is found that with a particular combination of electron thermal transport models, the average rms deviation of the predicted electron temperature profile from the experimental profile is reduced to 9% and the offset to -4%. [ABSTRACT FROM AUTHOR]

Grass species were grown in plots, as pure stands or mixed with wheat, after a sequence of wheat crops in which take-all ( Gaeumannomyces graminis var. tritici) had developed. Annual brome grasses maintained take-all inoculum in the soil as well as wheat (grown as a continuous sequence), and much better than cultivated species with a perennial habit. Take-all developed more in wheat grown after Anisantha sterilis (barren brome) or Bromus secalinus (rye brome), with or without wheat, than in continuous grass-free wheat in the same year, where take-all decline was apparently occurring. It was equally or more severe, however, in wheat grown after Lolium perenne (rye-grass) or Festuca arundinacea (tall fescue), despite these species having left the least inoculum in the soil. It was most severe in plots where these two grasses had been grown as mixtures with wheat. It is postulated that the presence of these grasses inhibited the development of take-all-suppressive microbiota that had developed in the grass-free wheat crops. The effects of the grasses appeared to be temporary, as amounts of take-all in a second subsequent winter wheat test crop were similar after all treatments. These results have important implications for take-all risk in wheat and, perhaps, other cereal crops grown after grass weed-infested cereals or after set-aside or similar 1-year covers containing weeds or sown grasses, especially in combination with cereal volunteers. They also indicate that grasses might be used experimentally in wheat crop sequences for investigating the mechanisms of suppression of, and conduciveness to, take-all. [ABSTRACT FROM AUTHOR]

Field isolates ( n = 144) of the wheat take-all fungus Gaeumannomyces graminis var. tritici ( Ggt) were tested for sensitivity to silthiofam, a take-all-specific fungicide used as a seed treatment, and identified as A- or B-type by PCR–RFLP analysis of nuclear rDNA. A possible association was identified between polymorphisms in ITS2 of the nuclear rDNA and sensitivity to silthiofam. A Ggt-specific PCR assay was developed which simultaneously identified isolates of Ggt as A- or B-type, based on the polymorphisms in the nuclear rDNA. A highly significant correlation between Ggt type using the PCR assay and sensitivity to silthiofam was demonstrated in a collection of 358 isolates from three field experiments designed to test the effects of seed-treatment fungicides on take-all and Ggt populations in winter wheat. In one experiment the percentages of silthiofam-sensitive and B-type isolates were significantly less in populations from plots sown with silthiofam-treated seed in two consecutive years than in populations from plots sown with nontreated seed. However, silthiofam still provided a significant amount of control of take-all. The natural occurrence of fungicide-insensitive isolates, up to about 30% in soils in which the fungicide had never been used, is unusual. The new PCR assay provides a useful tool for studying the population structure of Ggt, and may provide a novel method for assessing the incidence of insensitivity to silthiofam (the target site for which has not yet been identified) in field populations of Ggt. [ABSTRACT FROM AUTHOR]

Thirty-seven antagonists, from a collection of 113 pre-screened microorganisms, were tested in field experiments on winter wheat for their ability to control ear blight and production of mycotoxins, particularly deoxynivalenol (DON), in grain by Fusarium culmorum and F. graminearum . Ears were spray-inoculated during anthesis with spore suspensions, first of test fungi and then of the pathogen. Isolates of F. equiseti were the most effective treatments. A strain of F. equiseti (G9) decreased DON consistently on wheat inoculated with F. culmorum , compared with the control, often by more than 70%. It performed well under severe disease pressure ( F. culmorum at 10 5 conidia mL -1 ) and similarly to a standard fungicide, tebuconazole. Percentages of diseased grains and amounts of DON corresponded well. Small quantities of nivalenol (NIV) occurred in grain samples after treatment with some F. equiseti strains. On wheat inoculated with F. graminearum , F. equisti G2 decreased the percentage diseased grains by 92% and DON by 94%. One strain of F. equiseti (G2) was found to produce small amounts of NIV in pure culture. [ABSTRACT FROM AUTHOR]

Relationships between the incidence and severity of brown foot rot and of pathogenic fungi, determined by diagnostic and quantitative PCR, were investigated during the growth of nine winter wheat crops in three cropping seasons. Microdochium nivale vars nivale and majus were the only brown foot rot pathogens present in significant amounts. Relationships between disease symptoms and amounts of pathogen DNA were often weak in early spring (when shoot-base symptoms are usually most difficult to ascribe to particular pathogens by visual examination) because of indistinct symptoms and small amounts of pathogen. Relationships were strongest during stem elongation. The amount of M. nivale in the tissues tended to decline in the summer as the plants matured, apparently disappearing partially from necrotic lesions to which it contributed, resulting in a weakened relationship between symptoms and pathogen DNA. Regression analyses of brown foot rot on amounts of M. nivale DNA for different wheat cultivars generally produced lines with similar slopes but were often most significant for the cultivar with most eyespot resistance (i.e. with least confounding eyespot) or most apparently genuine brown foot rot. DNA of Fusarium spp. was rarely present in amounts sufficient to quantify. [ABSTRACT FROM AUTHOR]

Diagnostic and quantitative polymerase chain reaction (PCR) provided clarification of the causes of symptoms and the extent of infection by eyespot (Tapesia spp.) and sharp eyespot (Rhizoctonia cerealis) on winter wheat at early growth stages. Disease assessments made before stem extension, when decisions to apply fungicides are usually made, often did not agree with the pathogen diagnoses using PCR, suggesting that such early visual diagnoses may be unreliable. Visual and PCR diagnoses made on stems in summer generally supported each other, but there were often discrepancies in relating disease severity to amounts of pathogen present when determined by regression analyses of incidence or severity of symptoms on amount of pathogen DNA. Mixed symptoms caused by different pathogens may sometimes have been confounded. Relationships between symptoms and DNA of eyespot pathogens were less clear on some cultivars, often those with least disease. Sharp eyespot symptoms had a stronger relationship to DNA of its pathogen. Significant regressions often accounted for a small percentage of the variance, suggesting either that pathogens not assayed were contributing to symptoms or that lesions were in some cases persisting longer into the season than pathogen DNA. The frequency of pathogen detection before stem extension was a poor predictor of the amounts of pathogen DNA measured later in the season. [ABSTRACT FROM AUTHOR]