Quantification of the risk of Phytophthora dieback in The Greater Blue Mountains World Heritage area

Biological invasions exert great pressure on natural ecosystems and conservation areas, the latter of which have been established to conserve biodiversity. The presence of invasive species in natural ecosystems disrupts evolutionary processes, alters species abundance and can potentially lead to extinction (Mack et al., 2000; Crowl et al., 2008). When an invasive species is the cause of plant disease, the potential for that pathogen to survive in a new environment and the expectation of the impacts it may cause, can be estimated from locations where it already occurs. Understanding the dynamics of disease is important for management and research alike, and will hopefully make way for a proactive rather than reactive response. Disease in natural Australian ecosystems caused by the invasive species Phytophthora cinnamomi has been recognised for nearly 100 years (Newhook and Podger, 1972); its devastating impacts have lead to the disease syndrome, Phytophthora dieback, being classified as a Key Threatening Process by the Australian Federal Government (Commonwealth of Australia, 2005). Yet, the assessment of potential disease establishment, that is, disease risk, is limited. This remains true for the globally significant Greater Blue Mountains World Heritage Area (GBMWHA) in New South Wales, a centre of plant and animal conservation. Not only is the understanding of the pathogen distribution limited, so too is knowledge of the potential impacts on flora and the influence climate change may have on disease expression. Management of Phytophthora dieback in the GBMWHA is made increasingly complex by the rugged and remote nature of much of the World Heritage Area, as well as competing demands from tourism, recreation and the impacts of fire and other introduced species. This study aims to address some of these complexities by establishing the suitability of the GBMWHA to P. cinnamomi, its current distribution and the potential for disease. Additionally, with the difficulty of accessing much of the GBMWHA and the risk of disease transmission in mind, an alternate approach to disease identification is trialed. The first task of this project, was concerned with understanding the potential distribution of P. cinnamomi within the GBMWHA using mechanistic modelling and information on the pathogen’s ecology. Most of the GBMHWA was found to be suitable, leading to the acceptance of the first hypothesis that the climatic and topographic conditions of the GBMWHA are conducive to P. cinnamomi establishment. The most conducive areas were characterised by high soil wetness, high rainfall and moderate temperatures, while the areas least conducive were conversely hotter and drier. Although iv the model appeared to overpredict into areas the pathogen was not found, increasing distribution risk was associated with increasing isolations, possibly indicating that the pathogen is yet to reach its potential niche. The modelled distribution of P. cinnamomi was then used to inform a field investigation to determine the actual distribution in the GBMWHA and assess the impact of the pathogen on vegetation communities and individuals. As an invasive species, the distribution of P. cinnamomi was hypothesised to be primarily found in locations with high anthropogenic activity; however it was isolated extensively from remote areas, leading to the rejection of this hypothesis. Disease was never the less expected, albeit sporadic, as per disease expression in other vegetation communities in New South Wales (Arentz, 1974; Walsh et al., 2006; Howard, 2008). Heathland communities that often have a higher incidence of disease (McDougall and Summerell, 2003), had a high rate of pathogen isolation, as well as clear indications of disease in the GBMWHA. Additionally, freshwater wetlands, many of which are endangered ecological communities under Commonwealth and State legislation, had a high rate of pathogen isolation also. The results collected during the field work were then utilised to assess the risk of Phytophthora dieback occurring in the GBMWHA within the context of the disease triangle. The distribution of P. cinnamomi was combined with models of over 130 individual host species to produce a spatially explicit model, quantifying the risk of disease. That a large portion of the GBMWHA is at risk of Phytophthora dieback was not the case, and as such this hypothesis was rejected. Although much of the World Heritage Area had a least some level of risk, greatest risk was associated with a few small areas that occurred at higher elevations with suitable rainfall and temperature conditions. Unfortunately, many of these locations were associated with high levels of tourism and recreation, highlighting the potential for anthropogenic dispersal of P. cinnamomi into, around and out of the GBMWHA. Disease itself has a temporal element which cannot be quantified in one set of field results and as disease spreads the results become outdated quickly (O'Gara et al., 2005). Field-based assessments of disease are expensive and time consuming, and in area as vast and rugged as the GBMWHA, difficult and potentially dangerous. Real-time information on the impacts of disease are therefore needed by land managers to efficiently deploy management strategies (O'Gara et al., 2005). Remote sensing offers an alternative means of assessment not requiring site entry. Vegetation condition can be assessed remotely in all manner of plant systems including the detection and quantification of disease. As such, it was hypothesised here that infection caused by P. cinnamomi could be detected fro

Influence of sensitization and allergen provocation procedures on the development of allergen-induced bronchial hyperreactivity in conscious, unrestrained guinea-pigs

The effects of different sensitization and allergen provocation regimens on the development of allergen-induced bronchial hyperreactivity (BHR) to histamine were investigated in conscious, unrestrained guinea-pigs. Similar early and late phase asthmatic reactions, BHR for inhaled histamine after the early (6 h) as well as after the late reaction (24 h), and airway inflammation were observed after a single allergen provocation in animals sensitized to produce mainly IgG or IgE antibodies, respectively. Repeating the allergen provocation in the IgE-sensitized animals after 7 days, using identical provocation conditions, resulted in a similar development of BHR to histamine inhalation. Repetition of the allergen provocation during 4 subsequent days resulted in a decreased development of BHR after each provocation, despite a significant increase in the allergen provocation dose necessary to obtain similar airway obstruction. The number of inflammatory cells in the bronchoalveolar lavage was not significantly changed after repeated provocation, when compared with a single allergen provocation. Finally, we investigated allergen-induced bronchial hyperreactivity by repetition of the sensitization procedure at day 7 and 14 (booster), followed by repeated allergen provocation twice a week for 5 weeks. Surprisingly, no BHR to histamine could be observed after either provocation, while the number of inflammatory cells in the bronchoalveolar lavage fluid after 5 weeks was enhanced compared with controls. These data indicate that both IgE and IgG sensitized guinea-pigs may develop bronchial hyperreactivity after a single allergen provocation. Repeated allergen exposure of IgE sensitized animals causes a gradual fading of the induced hyperreactivity despite the on-going presence of inflammatory cells in the airways, indicating a mechanism of reduced cellular activation

The great arteries in normal and some congenitally malformed hearts their internal calibres and tunica media in relation to blood flow

The road from fertilized egg to newborn baby is a fascinating and complicated one. What happens to eggs that actually come in contact with spenns has been stuclied by many authors and has been summarized by Witschi in 1969. About 16% of the eggs do not cleave, either because they are not penetrated by sperms or because the mitotic mechanism does not function. Another 15% are lost during the first week, at various preimplantation stages ( cleavage and blastocyst stages ). The stage of early implantation and development during the second week brings a further lossof 27%. In the third to sixth week there is a loss of 8% and the late abortion loss is about 3%. Live births will then amount to only 31%. It has been shown that 1-12% of all these newborn children carry some major congenital malformation recognizable at or shortly after birth ( Yerushalmy, 1969; Lilienfeld, 1969 ), Reports of congenital malformations show congenital heart malformations in about 0.8% of total births ( Kerrebijn, 1964; Hoffman and Christianson, 1978 ). In the Netherlands with 177.090 newborns in 1976 this will be about 1400 per year of which 123 were surgically corrected and 416 died in the first year of life ( Centraal Bureau voor Statistiek, 1976, 1978 ). The majority of congenital he'art malfonnations are of rmknown etiology and are believed to be the result of the interaction of environmental and genetic influences ( Nora, 1968 ). The risk for recurrence of the same lesion in cases with an affected parent or sibling is small but exceeds the expectation risk for the same lesion in the general population. Vertical transmission of atrial septal defects through four generations has been described (Lynch et al., 1978 ) . These children bom with congenital heart malfonnations are of special interest to the paediatric cardiologist and cardiovascular surgeon

Epidemiological Interactions between Urogenital and Intestinal Human Schistosomiasis in the Context of Praziquantel Treatment across Three West African Countries

© 2015 Knowles et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

Estimates on returnable packaging material

When a beer company replaces its returnable packaging materials, for exam-ple when updating the design of a bottle, it needs to know in advance how much new material will be needed. Dutch beer brewer Heineken submitted the question of estimating the returnable packaging materials to the 2013 Studygroup Mathe-matics with Industry. In this report, we present both stochastic flow models and a queueing model to estimate the amount of returnable packaging material present in the market. Furthermore, we give recommendations on what data to collect, and how to sample this data in an unbiased way in order to increase accuracy of the estimation. Keywords: Modelling, Markov Chain, Stochastic Differential Equation, Queue-ing Theor

Rectification of thermal fluctuations in ideal gases

We calculate the systematic average speed of the adiabatic piston and a thermal Brownian motor, introduced in [Van den Broeck, Kawai and Meurs, \emph{Microscopic analysis of a thermal Brownian motor}, to appear in Phys. Rev. Lett.], by an expansion of the Boltzmann equation and compare with the exact numerical solution.Comment: 18 page