Eutrophication weakens stabilizing effects of diversity in natural grasslands

Studies of experimental grassland communities have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change. Here we analyse diversity-stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.

Considering the economic value of natural design elements at city scale

With increasing signs of climate change and the influence of national and international carbon-related laws and agreements, governments all over the world are grappling with how to rapidly transition to low-carbon living. This includes adapting to the impacts of climate change that are very likely to be experienced due to current emission levels (including extreme weather and sea level changes), and mitigating against further growth in greenhouse gas emissions that are likely to result in further impacts. Internationally, the concept of ‘Biophilic Urbanism’, a term coined by Professors Tim Beatley and Peter Newman to refer to the use of natural elements as design features in urban landscapes, is emerging as a key component in addressing such climate change challenges in rapidly growing urban contexts. However, the economics of incorporating such options is not well understood and requires further attention to underpin a mainstreaming of biophilic urbanism. Indeed, there appears to be an ad hoc, reactionary approach to creating economic arguments for or against the design, installation or maintenance of natural elements such as green walls, green roofs, streetscapes, and parklands. With this issue in mind, this paper will overview research as part of an industry collaborative research project that considers the potential for using a number of environmental economic valuation techniques that have evolved over the last several decades in agricultural and resource economics, to systematically value the economic value of biophilic elements in the urban context. Considering existing literature on environmental economic valuation techniques, the paper highlights opportunities for creating a standardised language for valuing biophilic elements. The conclusions have implications for expanding the field of environmental economic value to support the economic evaluations and planning of the greater use of natural elements in cities. Insights are also noted for the more mature fields of agricultural and resource economics.

An exploration into retrofitting cities with natural design elements - learning from the city of Berlin, Germany

Natural design features in the built environment or biophilic elements are emerging as a potential response to the challenges of climate change, urbanisation and population pressures which have invited issues such as rising urban heat island effect, rising pollution, increased congestion, among others. This concept of living cities was made popular by Professor Tim Beatley in his book titled ‘Biophilic Urbanism’. Evidence of biophilic urbanism can be seen in some cities from around the globe since decoupling environmental pressures from future development is a priority on many agendas. Berlin is an example of a modern economy that has adopted an ecological sustainable development approach to reduce environmental degradation while driving innovation and employment.

A simple method for EPID-based in vivo dosimetry for radiotherapy treatments of head-and-neck cancers

This study used a homogeneous water-equivalent model of an electronic portal imaging device (EPID), contoured as a structure in a radiotherapy treatment plan, to produce reference dose images for comparison with in vivo EPID dosimetry images. Head and neck treatments were chosen as the focus of this study, due to the heterogeneous anatomies involved and the consequent difficulty of rapidly obtaining reliable reference dose images by other means. A phantom approximating the size and heterogeneity of a typical neck, with a maximum radiological thickness of 8.5 cm, was constructed for use in this study. This phantom was CT scanned and a simple treatment including five square test fields and one off-axis IMRT field was planned. In order to allow the treatment planning system to calculate dose in a model EPID positioned a distance downstream from the phantom to achieve a source-to-detector distance (SDD) of 150 cm, the CT images were padded with air and the phantom’s “body” contour was extended to encompass the EPID contour. Comparison of dose images obtained from treatment planning calculations and experimental irradiations showed good agreement, with more than 90% of points in all fields passing a gamma evaluation, at γ (3%, 3mm )Similar agreement was achieved when the phantom was over-written with air in the treatment plan and removed from the experimental beam, suggesting that water EPID model at 150 cm SDD is capable of providing accurate reference images for comparison with clinical IMRT treatment images, for patient anatomies with radiological thicknesses ranging from 0 up to approximately 9 cm. This methodology therefore has the potential to be used for in vivo dosimetry during treatments to tissues in the neck as well as the oral and nasal cavities, in the head-and-neck region.

State of Energy Efficiency Education in Australian Technical & Further Education (TAFE) : A Report to the Australian Government Skills for the Carbon Challenge Initiative, The Natural Edge Project (TNEP), Queensland University of Technology

The Australian Government’s Skills for the Carbon Challenge (SCC) initiative aims to accelerate industry and the education sectors response to climate change. As part of the SCC initiative, the Department of Industry, Innovation, Climate Change, Science, Research and Tertiary Education (DIICCSRTE) provided funding to investigate the state of energy efficiency education in engineering-related Australian Technical and Further Education (TAFE) Programs. The following document reports on the outcomes of a multi-stage consultation project that engaged with participants from over 80% of TAFE institutions across Australia with the aim of supporting and enhancing future critical skills development in this area. Specifically, this report presents the findings of a national survey, based on a series of TAFE educator focus groups, conducted in May 2013 aimed at understanding the experiences and insights of Australian TAFE educators teaching engineering-related courses. Responses were received from 224 TAFE Educators across 50 of the 61 TAFE institutions in Australia (82% response rate).

Carbon, biodiversity and regional natural resource planning : towards high impact next generation plans

Given the increased importance of adaptation debates in global climate negotiations, pressure to achieve biodiversity, food and water security through managed landscape-scale adaptation will likely increase across the globe over the coming decade. In parallel, emerging market-based, terrestrial greenhouse gas abatement programs present a real opportunity to secure such adaptation to climate change through enhanced landscape resilience. Australia has an opportunity to take advantage of such programs through regional planning aspects of its governance arrangements for NRM. This paper explores necessary reforms to Australia's regional NRM planning systems to ensure that they will be better able to direct the nation's emerging GGA programs to secure enhanced landscape adaptation. © 2013 Planning Institute Australia.

Biophilic urbanism : harnessing natural elements to enhance the performance of constructed assets

Creating climate resilient, low-carbon urban environments and assets is a policy goal of many governments and city planners today, and an important issue for constructed asset owners. Stakeholders and decision makers in urban environments are also responding to growing evidence that cities need to increase their densities to reduce their footprint in the face of growing urban populations. Meanwhile, research is highlighting the importance of balancing such density with urban nature, to provide a range of health and wellbeing benefits to residents as well as to mitigate the environmental and economic impacts of heavily built up, impervious urban areas. Concurrently achieving this suite of objectives requires the coordination and cooperation of multiple stakeholder groups, with urban development and investment increasingly involving many private and public actors. Strategies are needed that can provide ‘win-win’ outcomes to benefit these multiple stakeholders, and provide immediate benefits while also addressing the emerging challenges of climate change, resource shortages and urban population growth. Within this context, ‘biophilic urbanism’ is emerging as an important design principle for buildings and urban areas. Through the use of a suite of natural design elements, biophilic urbanism has the potential to address multiple pressures related to climate change, increasing urban populations, finite resources and human’s inherent need for contact with nature. The principle directs the creation of urban environments that are conducive to life, delivering a range of benefits to stakeholders including building owners, occupiers and the surrounding community. This paper introduces the principle of biophilic urbanism and discusses opportunities for improved building occupant experience and performance of constructed assets, as well as addressing other sustainability objectives including climate change mitigation and adaptation. The paper presents an emerging process for considering biophilic design opportunities at different scales and highlights implications for the built environment industry. This process draws on findings of a study of leading cities internationally and learnings related to economic and policy considerations. This included literature review, two stakeholder workshops, and extensive industry consultation, funded by the Sustainable Built Environment National Research Centre through core project partners Western Australian Department of Finance, Parsons Brinckerhoff, Townsville City Council CitySolar Program, Green Roofs Australasia, and PlantUp.

Variation in risk seeking behaviour following large losses : a natural experiment

This study explores people's risk taking behaviour after having suffered large real-world losses following a natural disaster. Using the margins of the 2011 Australian floods (Brisbane) as a natural experimental setting, we find that homeowners who were victims of the floods and face large losses in property values are 50% more likely to opt for a risky gamble -- a scratch card giving a small chance of a large gain ($500,000) -- than for a sure amount of comparable value ($10). This finding is consistent with prospect theory predictions regarding the adoption of a risk-seeking attitude after a loss.

Generating natural language texts from business process models

Process Modeling is a widely used concept for understanding, documenting and also redesigning the operations of organizations. The validation and usage of process models is however affected by the fact that only business analysts fully understand them in detail. This is in particular a problem because they are typically not domain experts. In this paper, we investigate in how far the concept of verbalization can be adapted from object-role modeling to process models. To this end, we define an approach which automatically transforms BPMN process models into natural language texts and combines different techniques from linguistics and graph decomposition in a flexible and accurate manner. The evaluation of the technique is based on a prototypical implementation and involves a test set of 53 BPMN process models showing that natural language texts can be generated in a reliable fashion.

Commissioning of a new commercial plastic scintillator system for radiotherapy

Introduction Since 1992 there have been several articles published on research on plastic scintillators for use in radiotherapy. Plastic scintillators are said to be tissue equivalent, temperature independent and dose rate independent [1]. Although their properties were found to be promising for measurements in megavoltage X-ray beams there were some technical difficulties with regards to its commercialisation. Standard Imaging has produced the first commercial system which is now available for use in a clinical setting. The Exradin W1 scintillator device uses a dual fibre system where one fibre is connected to the Plastic Scintillator and the other fibre only measures Cerenkov radiation [2]. This paper presents results obtained during commissioning of this dosimeter system. Methods All tests were performed on a Novalis Tx linear accelerator equipped with a 6 MV SRS photon beam and conventional 6 and 18 MV X-ray beams. The following measurements were performed in a Virtual Water phantom at a depth of dose maximum. Linearity: The dose delivered was varied between 0.2 and 3.0 Gy for the same field conditions. Dose rate dependence: For this test the repetition rate of the linac was varied between 100 and 1,000 MU/min. A nominal dose of 1.0 Gy was delivered for each rate. Reproducibility: A total of five irradiations for the same setup. Results The W1 detector gave a highly linear relationship between dose and the number of Monitor Units delivered for a 10 9 10 cm2 field size at a SSD of 100 cm. The linearity was within 1 % for the high dose end and about 2 % for the very low dose end. For the dose rate dependence, the dose measured as a function of repetition the rate (100–1,000 MU/min) gave a maximum deviation of 0.9 %. The reproducibility was found to be better than 0.5 %. Discussion and conclusions The results for this system look promising so far being a new dosimetry system available for clinical use. However, further investigation is needed to produce a full characterisation prior to use in megavoltage X-ray beams.

Prostate radiotherapy treatment plan quality : effects of hip prostheses

Introduction This study aimed to examine the geometric and dosimetric results when radiotherapy treatment plans are designed for prostate cancer patients with hip prostheses. Methods Ten EBRT treatment plans for localised prostate cancer, in the presence of hip prostheses, were analysed and compared with a reference set of 196 treatment plans for localised prostate cancer in patients without prostheses. Crowe et al.’s TADA code [1] was used to extract treatment plan parameters and evaluate doses to target volumes and critical structures against recommended goals [2] and constraints [3, 4]. Results The need to avoid transmitting the radiation beam through the hip prostheses limited the range of gantry angles available for use in both the rotational (VMAT) and the non-rotational (3DCRT and IMRT) radiotherapy treatments. This geometric limitation (exemplified in the VMAT data shown in Fig. 1) reduced the overall quality of the treatment plans for patients with prostheses compared to the reference plans. All plans with prostheses failed the PTV dose homogeneity requirement [2], whereas only 4 % of the plans without prostheses failed this test. Several treatment plans for patients with hip prostheses also failed the QUANTEC requirements that less than 50 % of the rectum receive 50 Gy and less than 35 % of the rectum receive 60 Gy to keep the grade 3 toxicity rate below 10 % [3], or the Hansen and Roach requirement that less than 25 % of the bladder receive 75 Gy [4]. Discussion and conclusions The results of this study exemplify the difficulty of designing prostate radiotherapy treatment plans, where beams provide adequate doses to targeted tissues while avoiding nearby organs at risk, when the presence of hip prostheses limits the available treatment geometries. This work provides qualitative evidence of the compromised dose distributions that can result, in such cases.

Development of a dose assessment tool for the auditing of radiotherapy treatment dosimetric quality

The reporting and auditing of patient dose is an important component of radiotherapy quality assurance. The manual extraction of dose-volume metrics is time consuming and undesirable when auditing the dosimetric quality of a large cohort of patient plans. A dose assessment application was written to overcome this, allowing the calculation of various dose-volume metrics for large numbers of plans exported from treatment planning systems. This application expanded on the DICOM-handling functionality of the MCDTK software suite. The software extracts dose values in the volume of interest by using a ray casting point-in-polygon algorithm, where the polygons have been defined by the contours in the RTSTRUCT file...

Gel dosimetry—it’s been the next big thing in radiotherapy for the past 25 years

Gel dosimetry and plastic chemical dosimeters such as PresageTM are capable of very accurately mapping dose distributions in three dimensions. Combined with their near tissue equivalence one would expect that after several decades of development they would be the dosimeter of choice for dosimetry, however they have not achieve widespread clinical use. This presentation will include a brief description and history of developments in gels and 3D plastics for dosimetry, the limitations and advantages, and their role in the future.

CTCombine : rotating and combining CT data with an accurate detector model to simulate radiotherapy portal imaging at non-zero beam angles

Established Monte Carlo user codes BEAMnrc and DOSXYZnrc permit the accurate and straightforward simulation of radiotherapy experiments and treatments delivered from multiple beam angles. However, when an electronic portal imaging detector (EPID) is included in these simulations, treatment delivery from non-zero beam angles becomes problematic. This study introduces CTCombine, a purpose-built code for rotating selected CT data volumes, converting CT numbers to mass densities, combining the results with model EPIDs and writing output in a form which can easily be read and used by the dose calculation code DOSXYZnrc...

Unsteady natural convection within a porous enclosure of sinusoidal corrugated side walls

Numerically investigation of free convection within a porous cavity with differential heating has been performed using modified corrugated side walls. Sinusoidal hot left and cold right walls are assumed to receive sudden differentially heating where top and bottom walls are insulated. Air is considered as working fluid and is quiescent, initially. Numerical experiments reveal 3 distinct stages of developing pattern including initial stage, oscillatory intermediate and finally steady state condition. Implicit Finite Volume Method with TDMA solver is used to solve the governing equations. This study has been performed for the Rayleigh numbers ranging from 100 to 10,000. Outcomes have been reported in terms of isotherms, streamline, velocity and temperature plots and average Nusselt number for various Ra, corrugation frequency and corrugation amplitude. The effects of sudden differential heating and its resultant transient behavior on fluid flow and heat transfer characteristics have been shown for the range of governing parameters. The present results show that the transient phenomena are enormously influenced by the variation of the Rayleigh Number with corrugation amplitude and frequency.