Isolation and pathogenicity of Phytophthora species from declining Rubus anglocandicans

Rubus anglocandicans is the most widespread and abundant blackberry species within the European blackberry (Rubus fruticosus) aggregate in Western Australia (WA). European blackberry is also one of the 32 Weeds of National Significance in Australia. A disease recorded as 'blackberry decline' was first observed in some blackberry sites in WA in 2006. A disease survey was conducted in the Manjimup-Pemberton region along the Warren and Donnelly River catchments in WA between 2010 and 2012. Phytophthora amnicola, P. bilorbang, P. cryptogea, P. inundata, P. litoralis, P. multivora, P. taxon personii, P. thermophila and a P. thermophila × amnicola hybrid were recovered from declining and adjacent decline-free sites, as well as from streams and rivers. Phytophthora cinnamomi was isolated from dying Banksia and Eucalyptus species from two non-decline sites. Of these species, P. bilorbang and P. cryptogea were more pathogenic than the others in under-bark inoculations using excised stems (primocanes), in planta primocane inoculations in blackberry growing wild in native forest stands, and in glasshouse pot trials. It was concluded that blackberry decline is a complex syndrome and Phytophthora species, in particular P. bilorbang and P. cryptogea, together with temporary inundation, are major biotic and abiotic factors contributing to blackberry decline

The conjugacy problem for the automorphism group of the random graph

We prove that the conjugacy problem for the automorphism group of the random graph is Borel complete, and discuss the analogous problem for some other countably categorical structures.Comment: 7 page

Development of a Ground-Based Analog to the Advanced Resistive Exercise Device Aboard the International Space Station

NASA and Wyle engineers constructed a Horizontal Exercise Fixture (HEF) that was patented in 2006. Recently modifications were made to HEF with the goal of creating a device that mimics squat exercise on the Advanced Resistive Exercise Device (ARED) and can be used by bed rest subjects who must remain supine during exercise. This project posed several engineering challenges, such as how best to reproduce the hip motions (we used a sled that allowed hip motion in the sagittal plane), how to counterweight the pelvis against gravity (we used a pulley and free-weight mechanism), and how to apply large loads (body weight plus squat load) to the shoulders while simultaneously supporting the back against gravity (we tested a standard and a safety bar that allowed movement in the subject s z-axis, both of which used a retractable plate for back support). METHODS An evaluation of the HEF was conducted with human subjects (3F, 3M), who performed sets of squat exercises of increasing load from 10-repetition maximum (RM) up to 1-RM. Three pelvic counterweight loads were tested along with each of the two back-support squat bars. Data collection included 3-dimensional ground reaction forces (GRF), muscle activation (EMG), body motion (video-based motion capture), and subjective comments. These data were compared with previous ground-based ARED study data. RESULTS All subjects in the evaluation were able to perform low- to high-loading squats on the HEF. Four of the 6 subjects preferred a pelvic counterweight equivalent to 60 percent of their body weight. Four subjects preferred the standard squat bar, whereas 2 female subjects preferred the safety bar. EMG data showed muscle activation in the legs and low back typical of squat motion. GRF trajectories and eccentric-concentric loading ratios were similar to ARED. CONCLUSION: Squat exercise performed on HEF approximated squat exercise on ARED

Fungi pathogenic on wild radish (Raphanus raphanistrum L.) in northern Tunisia

The distribution and life cycle of wild radish (Raphanus raphanistrum L.) and a survey of the pathogens of this plant are reported for the northern regions of Tunisia. Wild radish is a common weed of cereal crops and legumes. It germinates in early autumn (October), develops a rosette stage in November to December after which stem growth, fl owering and pod production occur through to May, with pod maturity completed in June. Fungus isolation from the foliar tissues exhibiting disease symptoms showed that wild radish was infected with the fungi Albugo candida, Alternaria spp. including A. brassicicola, and A. raphani, Erysiphe cruciferarum, Stemphylium herbarum, Peronospora parasitica and Phoma lingam. Ascochyta spp., Cercospora armoraciae, Cladosporium cladosporioides and Colletotrichum higginsianum are here reported from wild radish for the first time. Inoculation tests of pathogens on wild radish plants showed that the most injurious fungi were Alternaria raphani and Phoma lingam. The remaining pathogens were weakly to moderately aggressive on this weed. To access the pathogenic effect of fungi spontaneously infecting natural populations of wild radish, the weed was grown in a field experiment with and without the broad-spectrum systemic fungicide Carbendazim. Results showed a statistically significant two-fold decrease in the number and weight of seed pods in the non-treated plants, indicating that the reproductive potential of wild radish was naturally reduced by fungal infection. Foliar pathogenic fungi have a potential in the integrated weed management of wild radish, this role merits further investigations

Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control

This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York

A Hyperbaric Aerodynamic Levitator For Containerless Materials Research

A hyperbaric aerodynamic levitator has been developed for containerless materials research at specimen temperatures exceeding 2000 °C and pressures up to 10.3 MPa (1500 psi). This report describes the prototype instrument design and observations of the influence of specimen size, density, pressure, and flow rate on levitation behavior. The effect of pressure on heat transfer was also assessed by studying the heating and cooling behavior of levitated Al2O3 liquids. A threefold increase in the convective heat transfer coefficient was estimated as pressure increased to 10.3 MPa. The results demonstrate that hyperbaric aerodynamic levitation is a promising technique for containerless materials research at high gas pressures

Moving lattice kinks and pulses: an inverse method

We develop a general mapping from given kink or pulse shaped travelling-wave solutions including their velocity to the equations of motion on one-dimensional lattices which support these solutions. We apply this mapping - by definition an inverse method - to acoustic solitons in chains with nonlinear intersite interactions, to nonlinear Klein-Gordon chains, to reaction-diffusion equations and to discrete nonlinear Schr\"odinger systems. Potential functions can be found in at least a unique way provided the pulse shape is reflection symmetric and pulse and kink shapes are at least $C^2$ functions. For kinks we discuss the relation of our results to the problem of a Peierls-Nabarro potential and continuous symmetries. We then generalize our method to higher dimensional lattices for reaction-diffusion systems. We find that increasing also the number of components easily allows for moving solutions.Comment: 15 pages, 5 figure

Books

Medical audit Audit in Action. Ed. by Richard Smith. Pp. xiv + 245. Illustrated. £10,95. London: British Medical Journal. 1992. Available from Libriger Book Distributors, Bloemfontein.Rheumatology Bailliere's Clinical Rheumatology: Giant Cell Arteritis and Polymyalgia RheuIDatica. Guest eds B. L. Hazleman and B.-A. Bengtsson. Pp. xi + 507. illustrated. £27,50. London: Bailliere Tindall. 1991.AIDS, drugs and sexual risk AIDS, Drugs and Sexual Risk. By N. McKeganey and M. Bamard. Johannesburg: Random Century. 1992.Radiation When is a Dose Not a Dose? By Victor P. Bond. Pp. 39. Illustrated. Bethesda: National Council on Radiation Protection and Measurements. 1992.Autoimmune disease Clinical and Molecular Aspects of Autoimmune Diseases. Vol. 8. Ed. by J. M. Cruse and R. E. Lewis. Pp. x + 258. Illustrated. SFr. 248. Basel: Karger. 1992.Biochemical toxicology Principles of Biochemical Toxicology. 2nd ed. By J. A. Timbrel!. Illustrated. Pp. 415. RI53,73. London: Taylor & Frands. 1991.Advances in pineal research Advances in Pineal Research. Vol. 6. Ed. by Andrew Foldes and R. J. Reiter. pp. viii + 286. illustrated. £32,50. London: John Libbey. 1991.Health care for the future The Future of Health Care. Pp. 83. Illustrated. London: British Medical Journal. 1992.STDs and AIDS School Health Education to Prevent AIDS and Sexually Transmitted Disease. Pp. 79. SFr. 18. Geneva: World Health Organisation. 1992

Current and projected global distribution of Phytophthora cinnamomi, one of the world's worst plant pathogens

Globally, Phytophthora cinnamomi is listed as one of the 100 worst invasive alien species and active management is required to reduce impact and prevent spread in both horticulture and natural ecosystems. Conversely, there are regions thought to be suitable for the pathogen where no disease is observed. We developed a climex model for the global distribution of P. cinnamomi based on the pathogen's response to temperature and moisture and by incorporating extensive empirical evidence on the presence and absence of the pathogen. The climex model captured areas of climatic suitability where P. cinnamomi occurs that is congruent with all available records. The model was validated by the collection of soil samples from asymptomatic vegetation in areas projected to be suitable by the model for which there were few records. DNA was extracted, and the presence or absence of P. cinnamomi was determined by high-throughput sequencing (HTS). While not detected using traditional isolation methods, HTS detected P. cinnamomi at higher elevations in eastern Australia and central Tasmania as projected by the climex model. Further support for the climex model was obtained using the large data set from south-west Australia where the proportion of positive records in an area is related to the Ecoclimatic Index value for the same area. We provide for the first time a comprehensive global map of the current P. cinnamomi distribution, an improved climex model of the distribution, and a projection to 2080 of the distribution with predicted climate change. This information provides the basis for more detailed regional-scale modelling and supports risk assessment for governments to plan management of this important soil-borne plant pathogen