Swimming capabilities of stoats and the threat to inshore sanctuaries

Stoats (Mustela erminea) are small carnivorous mammals which were introduced into New Zealand in the late 19th century, and have now become widespread invasive pests. Stoats have long been known to be capable of swimming to islands 1-1.5 km offshore. Islands further out have usually been assumed to be safe from invasion, therefore routine stoat monitoring on them has been considered un-necessary. Recent incursions, including a stoat found on Rangitoto Island (3 km offshore) in 2010, and another which was deduced to have reached Kapiti (5 km offshore) in 2009, along with distribution modelling and genetic studies, strongly support the proposition that stoats can swim much further than 1.5 km. Acceptance of this hypothesis depends on estimating the probability that such small animals could indeed swim so far unaided. This paper reports the results of a project designed to assist this debate by recording the paddling action, speed and minimal endurance of nine stoats observed (once each) swimming against an endless current in a flume at the Aquatic Research Centre, University of Waikato. Four of the five males and two of the four females could hold a position for at least five minutes against the maximum current available, averaging 1.36 ± 0.336 km/h. In steady swimming against a current of c. 1 km/hr, they all used a rapid quadripedal paddling action (averaging 250 strokes/min, stronger with the spread forepaws). Four of the nine swam strongly for >1 h, including one female who covered 1.8 km in nearly 2 h non- stop. Results from such artificial conditions cannot be conclusive, but support suggestions that wild stoats could indeed swim much further than 1.5 km, hence we conclude that the “risk zone” for stoat reinvasions of inshore islands has been seriously under-estimated

Toward a theoretical model of quality-of-life appraisal: Implications of findings from studies of response shift

Mounting evidence for response shifts in quality of life (QOL) appraisal indicates the need to include direct measurement of the appraisal process itself as a necessary part of QOL assessment. We propose that directly assessing QOL appraisal processes will not only improve our ability to interpret QOL scores in the traditional sense, but will also yield a deeper understanding of the appraisal process in the attribution of and divergence in meaning. The published evidence for response shift is reviewed, and an assessment paradigm is proposed that includes the explicit measurement of QOL appraisal process parameters: 1) induction of a frame of reference; 2) recall and sampling of salient experiences; 3) standards of comparison used to appraise experiences; and 4) subjective algorithm used to prioritize and combine appraisals to arrive at a QOL rating. A QOL Appraisal Profile, which measures key appraisal processes, is introduced as an adjunct to existing QOL scales. The proposed theoretical model, building on the Sprangers and Schwartz (1999) model and highlighting appraisal processes, provides a fully testable theoretical treatment of QOL and change in QOL, suggesting hypothesized causal relationships and explanatory pathways for both cross-sectional and longitudinal QOL research

Reconsidering the psychometrics of quality of life assessment in light of response shift and appraisal

The increasing evidence for response shift phenomena in quality of life (QOL) assessment points to the necessity to reconsider both the measurement model and the application of psychometric analyses. The proposed psychometric model posits that the QOL true score is always contingent upon parameters of the appraisal process. This new model calls into question existing methods for establishing the reliability and validity of QOL assessment tools and suggests several new approaches for describing the psychometric properties of these scales. Recommendations for integrating the assessment of appraisal into QOL research and clinical practice are discussed

Hand Dominance and Walking Aid Use - Pre-determinants for Hip Fracture in the Elderly?

AIM: Left handedness has previously been associated with an increased risk of fracture for a number of sites but to the best of our knowledge no association between handedness and hip fracture has previously been reported. MATERIALS AND METHODS: Two separate 6-month prospective reviews of hip fracture patients aged over 65 years of age were conducted at two different hospitals, with the second review focusing on walking aid use. The patients with a neurological condition or contralateral hip prosthesis were excluded due to increased balance problems and falls risk. RESULTS: Hand dominance was recorded for 339 patients; 304 right and 35 left. A total of 91 patients were excluded from the study. Of the remaining 248 patients, 2.06 times as many fractured their hip on the side of their non-dominant hand. For the left-handed individuals this increased to 4.6 times. Walking aid use was recorded for 102 patients. Equal numbers of the right and left hip fractures were sustained for patients using no walking aids, a Zimmer frame or two walking sticks; while 97.7% of patients using one walking stick did so in their dominant hand, sustaining 84% contralateral hip fractures. CONCLUSION: The direction in which people fall and the causes of hip fractures is clearly multifactorial. However, we did find an association between hand dominance and hip fracture, especially when using a single walking aid. By being aware of this association, it may be possible to target both patient education and physiotherapy potentially reducing the number of patient falls and associated hip fractures

Solar Turbines Compressor Blade Installation Tools

The following report documents a California Polytechnic State University, Mechanical Engineering Senior Project sponsored by the gas turbine manufacturer, Solar Turbines. The senior project team consisted of four senior mechanical engineering students at Cal Poly, all with general concentrations; Ryan Bruce, Carolyn Honeycutt, Steve Oltrogge, and Emmett Ross. Kenneth Thomas sponsored the group and serves as the point of contact between the senior project team and Solar Turbines. He is a member of the Solar Turbines Mechanical Design Engineering Team and a Cal Poly graduate. Christoph Maurer served as the project team’s on-campus advisor. A gas turbine uses internal combustion to produce output shaft work and can be broken down into a “cold” section and a “hot” section. The cold section is composed of the air inlet and the air compressor, while the hot section is composed of the burner, turbine, and diffuser. This project was focused on the compressor, specifically compressor blade installation. Solar Turbines’ T130, Mars, and T250 turbines all contain multi-stage compressors, meaning that many sets of compressor blades spin around a single shaft to continually compress the air as it nears the burner. Many of the compressor stages are installed using a ring method, where the compressor blades are slid into large slots around the compressor rotor, radially, and held into place, axially, by a large ring. These stages require additional hardware to restrain the blades radially. However, the first several stages of the compressor use axially installed fan blades, where each blade slides into an individual slot on the rotor disk and is held in place, radially by the geometry of the compressor. These stages therefore require additional hardware to restrain the axial movement of the blades. This is accomplished via small steel retainer tabs. This project focuses on the installation of these metal retainer tabs. The current process for installing the early stage compressor blades, those requiring retainer tabs, involves several, individual, time-consuming steps. Additionally, there are numerous tools required for each of these steps and every individual installation technician can have an additional, personal set of installation tools. As a result compressor blade installation is a lengthy and imprecise process that leads to inconsistencies and risks damaging the compressor rotor. The task for the Cal Poly senior project group was to design a tool(s) and a corresponding standardized process to bend these retainer tabs into position. The sponsor, Solar Turbines, owns all Intellectual Property for the tools designed during the course of the project. In return, they provided funding for the project, access to necessary company proprietary information, manufacturing support (as needed), and general project guidance. The overall aim of this project was to design a tool or set of tools that removed as much of the variation from compressor blade retainer tab installation as possible. As well as reduced the time spent installing blades, therefore reducing the risk of damage to the turbine blades and rotors from non-standardized processes and tooling. Additionally the team focused on minimizes the number of tools used in the overall process. The final tool design consisted of two tools, a “backing” and a “bending” tool. Each should decrease the installation time, increase consistency, are more ergonomic, and are safer than the current methods

Resilience of New Zealand indigenous forest fragments to impacts of livestock and pest mammals

A number of factors have combined to diminish ecosystem integrity in New Zealand indigenous lowland forest fragments surrounded by intensively grazed pasture. Livestock grazing, mammalian pests, adventive weeds and altered nutrient input regimes are important drivers compounding the changes in fragment structure and function due to historical deforestation and fragmentation. We used qualitative systems modelling and empirical data from Beilschmiedia tawa dominated lowland forest fragments in the Waikato Region to explore the relevance of two common resilience paradigms – engineering resilience and ecological resilience – for addressing the conservation management of forest fragments into the future. Grazing by livestock and foraging/predation by introduced mammalian pests both have direct detrimental impacts on key structural and functional attributes of forest fragments. Release from these perturbations through fencing and pest control leads to partial or full recovery of some key indicators (i.e. increased indigenous plant regeneration and cover, increased invertebrate populations and litter mass, decreased soil fertility and increased nesting success) relative to levels seen in larger forest systems over a range of timescales. These changes indicate that forest fragments do show resilience consistent with adopting an engineering resilience paradigm for conservation management, in the landscape context studied. The relevance of the ecological resilience paradigm in these ecosystems is obscured by limited data. We characterise forest fragment dynamics in terms of changes in indigenous species occupancy and functional dominance, and present a conceptual model for the management of forest fragment ecosystems