Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector

Purpose Small field x-ray beam dosimetry is difficult due to a lack of lateral electronic equilibrium, source occlusion, high dose gradients and detector volume averaging. Currently there is no single definitive detector recommended for small field dosimetry. The objective of this work was to evaluate the performance of a new commercial synthetic diamond detector, namely the PTW 60019 microDiamond, for the dosimetry of small x-ray fields as used in stereotactic radiosurgery (SRS). Methods Small field sizes were defined by BrainLAB circular cones (4 – 30 mm diameter) on a Novalis Trilogy linear accelerator and using the 6 MV SRS x-ray beam mode for all measurements. Percentage depth doses were measured and compared to an IBA SFD and a PTW 60012 E diode. Cross profiles were measured and compared to an IBA SFD diode. Field factors, Ω_(Q_clin,Q_msr)^(f_clin,f_msr ), were calculated by Monte Carlo methods using BEAMnrc and correction factors, k_(Q_clin,Q_msr)^(f_clin,f_msr ), were derived for the PTW 60019 microDiamond detector. Results For the small fields of 4 to 30 mm diameter, there were dose differences in the PDDs of up to 1.5% when compared to an IBA SFD and PTW 60012 E diode detector. For the cross profile measurements the penumbra values varied, depending upon the orientation of the detector. The field factors, Ω_(Q_clin,Q_msr)^(f_clin,f_msr ), were calculated for these field diameters at a depth of 1.4 cm in water and they were within 2.7% of published values for a similar linear accelerator. The corrections factors, k_(Q_clin,Q_msr)^(f_clin,f_msr ), were derived for the PTW 60019 microDiamond detector. Conclusions We conclude that the new PTW 60019 microDiamond detector is generally suitable for relative dosimetry in small 6 MV SRS beams for a Novalis Trilogy linear equipped with circular cones.

Experienced-based management of IMRT quality assurance

This study uses the detailed, bulk analyses of a set of treatment planning and quality assurance data from one radiotherapy centre to provide an illuminating example of the provision evidence-based advice on the management, and potential reduction, of an IMRT quality assurance workload.

Making optimal and justifiable asset maintenance decisions

Maintenance decisions for large-scale asset systems are often beyond an asset manager's capacity to handle. The presence of a number of possibly conflicting decision criteria, the large number of possible maintenance policies, and the reality of budget constraints often produce complex problems, where the underlying trade-offs are not apparent to the asset manager. This paper presents the decision support tool "JOB" (Justification and Optimisation of Budgets), which has been designed to help asset managers of large systems assess, select, interpret and optimise the effects of their maintenance policies in the presence of limited budgets. This decision support capability is realized through an efficient, scalable backtracking- based algorithm for the optimisation of maintenance policies, while enabling the user to view a number of solutions near this optimum and explore tradeoffs with other decision criteria. To assist the asset manager in selecting between various policies, JOB also provides the capability of Multiple Criteria Decision Making. In this paper, the JOB tool is presented and its applicability for the maintenance of a complex power plant system.

Naik Naik

"Naik Naik, conceived and directed by Cheryl Stock, is a multi-site promenade performance in which the audience joins the artists in physically exploring the notion of ‘ascent’ through their upward journey from Fort A Famosa at the base of the hill to Site 1 of St Paul’s Hill at the summit. Beginning at dusk with vignette performances along the ascending path, the journey finishes on entering the church ruins at nightfall. An evocation of place through performative contemplations, this processional experience lingers on the traces of history that remain hidden or partially and silently exposed, interwoven with personal and cultural stories related to the sites, in a celebration of the present. Naik Naik brings together eight established and emerging professional artists whose disciplines range across dance, music, visual arts and media production. Excitingly, this will be the first performance at MAPFest arising from a pre-festival collaborative residency with development time in Malaysia for all artists to work on a new production from its inception. The collaboration has been based on ideas arising from site research as well as myths and local stories from longterm Melaka residents who contributed their knowledge and memories of the chosen sites. Naik Naik has been created by its artists in an acknowledgement of Melaka’s unique multicultural heritage and contemporary identity.

Q&A : Christy Dena

Dr. Christy Dena is a noted academic and transmedia writer, experience designer, and director whose work includes the 2011 Digital Emmy-nominated Conspiracy for Good and The Hunt for Cisco. Dena is currently working on AUTHENTIC IN ALL CAPS, an online comedy/drama. Q: How did you get into transmedia? Q: What would you recommend that transmedia creators learn about to improve their craft? Q: What are the most important things to keep in mind when you’re designing an interactive element...

Adverse weather effects on bus ridership

This study focuses on weather effects on daily bus ridership in Brisbane, given bus’ dominance in this city. The weather pattern of Brisbane varies by season according to its sub-tropical climate characteristics. Bus is prone to inclement weather condition as it shares the road system with general traffic. Moreover, bus stops generally offer less or sometimes no protection from adverse weather. Hence, adverse weather conditions such as rain are conjectured to directly impact on daily travel behaviour patterns. There has been limited Australian research on the impact of weather on daily transit ridership. This study investigates the relationship between rainy day and daily bus ridership for the period of 2010 to 2012. Overall, rainfall affects negatively with varying impacts on different transit groups. However, this analysis confirmed a positive relationship between consecutive rainy days (rain continuing for 3 or more days). A possible explanation could be that people may switch their transport mode to bus to avoid high traffic congestion and higher accident potentiality on rainy days. Also, Brisbane’s segregated busway (BRT) corridor works favourably towards this mode choice. Our study findings enhance the fundamental understanding of traveller behaviour, particularly mode choice behaviour under adverse weather conditions.

Environmental, personal, and genetic determinants of response to vitamin D supplementation in older adults

CONTEXT AND OBJECTIVE: Suboptimal vitamin D status can be corrected by vitamin D supplementation, but individual responses to supplementation vary. We aimed to examine genetic and nongenetic determinants of change in serum 25-hydroxyvitamin D (25(OH)D) after supplementation. DESIGN AND PARTICIPANTS: We used data from a pilot randomized controlled trial in which 644 adults aged 60 to 84 years were randomly assigned to monthly doses of placebo, 30 000 IU, or 60 000 IU vitamin D3 for 12 months. Baseline characteristics were obtained from a self-administered questionnaire. Eighty-eight single-nucleotide polymorphisms (SNPs) in 41 candidate genes were genotyped using Sequenom MassArray technology. Serum 25(OH)D levels before and after the intervention were measured using the Diasorin Liaison platform immunoassay. We used linear regression models to examine associations between genetic and nongenetic factors and change in serum 25(OH)D levels. RESULTS: Supplement dose and baseline 25(OH)D level explained 24% of the variability in response to supplementation. Body mass index, self-reported health status, and ambient UV radiation made a small additional contribution. SNPs in CYP2R1, IRF4, MC1R, CYP27B1, VDR, TYRP1, MCM6, and HERC2 were associated with change in 25(OH)D level, although only CYP2R1 was significant after adjustment for multiple testing. Models including SNPs explained a similar proportion of variability in response to supplementation as models that included personal and environmental factors. CONCLUSION: Stepwise regression analyses suggest that genetic variability may be associated with response to supplementation, perhaps suggesting that some people might need higher doses to reach optimal 25(OH)D levels or that there is variability in the physiologically normal level of 25(OH)D.

Health consequences of exposure to brominated flame retardants : a systematic review

Background Brominated flame retardants (BFRs), are chemicals widely used in consumer products including electronics, vehicles, plastics and textiles to reduce flammability. Experimental animal studies have confirmed that these compounds may interfere with thyroid hormone homeostasis and neurodevelopment but to date health effects in humans have not been systematically examined. Objectives To conduct a systematic review of studies on the health impacts of exposure to BFRs in humans, with a particular focus on children. Methods A systematic review was conducted using the Medline and EMBASE electronic databases up to 1 February 2012. Published cohort, cross-sectional, and case-control studies exploring the relationship between BFR exposure and various health outcomes were included. Results In total, 36 epidemiological studies meeting the pre-determined inclusion criteria were included. Plausible outcomes associated with BFR exposure include diabetes, neurobehavioral and developmental disorders, cancer, reproductive health effects and alteration in thyroid function. Evidence for a causal relationship between exposure to BFRs and health outcomes was evaluated within the Bradford Hill framework. Conclusion Although there is suggestive evidence that exposure to BFRs is harmful to health, further epidemiological investigations particularly among children, and long-term monitoring and surveillance of chemical impacts on humans are required to confirm these relationships.

Commercial friendships between gay salesmen and straight female customers

Perhaps it is now sacrosanct in marketing to contemplate that many service encounters, especially those in retail settings, are social encounters in which bonds between and among customers and employees are critical drivers of consumption (Beatty et al., 1996; Rosenbaum, 2006). Indeed, within retail settings, it is often possible for salespeople and customers to form so-called “commercial friendships” (Price and Arnould, 1999). These friendships result in both salespeople and their customers having social interactions that are close to those experienced in personal friendships (Swan et al., 2001), and which are extremely satisfying for all parties. Outside of marketing, the social science literature (Grigoriou, 2004; Rumens, 2008; Russell, DelPriore, Butterfield, and Hill, 2013) and popular press (de la Cruz and Dolby, 2007; Hopcke and Rafaty, 1999; Tilmann-Healy, 2001, Whitney, 1990) is replete with knowledge regarding the “absolutely fabulous” friendships (Hopcke and Rafaty, 1999) that often form between gay men and straight women. In fact, Western culture regularly highlights the compatibility of gay men and straight women in film, television, and writing, to the extent that they have now influenced popular thinking on the topic, so that gay men and straight females are viewed as sharing common plights and interests (Rumens, 2008). Yet, thus far, marketing researchers have looked askance at the effect of friendships between gay male employees and heterosexual female customers in consumption settings, such as retail stores and boutiques. Indeed, with the exception of Peretz’s (1995) participant observation regarding how young and outwardly gay salesmen use their ambiguous gender to sell women’s clothing, in a Paris-based luxury boutique, any theoretical explorations regarding retail-based commercial friendships between gay salesmen and female customers are non-existent—until now. This research addresses this apparent chasm in the literature by putting forth an original framework that shows how the emotional closeness between gay salesmen and female customers, due to the absence of sexual interest and inter-female competition, results in an intense emotional closeness, that facilitates pleasurable retail transactions, customer satisfaction, loyalty, and positive word-of-mouth. In doing so, this work extends the commercial friendship paradigm by considering retail-based, commercial friendships between an under-researched marketplace dyad; gay men and straight females. It is worth noting here that some straight women may find the idea of commercial friendships with gay salesmen as undesirable, due to the very notion of having relationships with retail organizations or employees (Noble and Phillips, 2004), or a personal disdain for homosexuality.

Once more into the mire, dear friends : determining the existence of a duty of care in negligence

There were signs in the 1997 High Court decision in Hill v Van Erp that the different members of the bench were beginning to move in the same direction when it came to the tort equivalent of the search for the Holy Grail, a common approach to the determination of the existence of a duty of care in negligence. However, the court's subsequent decision in Perre v Apand signaled a slide back to uncertainty with the seven judges favouring five different approaches. This Note examines those five approaches in the search for guidance for those at the "coalface" - litigants, their legal advisers and trial judges.

Emerging Planning Frameworks for Climate Adaptation

This chapter focuses on the more strategic activities that lead people in the regional community to decide how they want to respond to climate change. Such strategic activities include analysing, prioritising and deciding upon the best course of action. Planning for climate adaptation (usually seen to include the setting of visions and objectives, the determination of key strategies and the monitoring of broad outcomes) encompasses the strategic activities involved in the system of governance for climate adaptation. Planning occurs at all scales from global to the business, property, family and even individual scales. Applying a rapid appraisal technique, this chapter analyses the system of planning for climate adaptation as it relates to the achievement of adaptation outcomes within the Wet Tropics Cluster. It finds that some aspects of the system are healthier than others, and identifies several actions that regional NRM bodies may consider (either collectively or individually) to enhance adaptation outcomes by improving the planning system within the cluster.