173 research outputs found

    Behavioural Response Thresholds in New Zealand Crab Megalopae to Ambient Underwater Sound

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    A small number of studies have demonstrated that settlement stage decapod crustaceans are able to detect and exhibit swimming, settlement and metamorphosis responses to ambient underwater sound emanating from coastal reefs. However, the intensity of the acoustic cue required to initiate the settlement and metamorphosis response, and therefore the potential range over which this acoustic cue may operate, is not known. The current study determined the behavioural response thresholds of four species of New Zealand brachyuran crab megalopae by exposing them to different intensity levels of broadcast reef sound recorded from their preferred settlement habitat and from an unfavourable settlement habitat. Megalopae of the rocky-reef crab, Leptograpsus variegatus, exhibited the lowest behavioural response threshold (highest sensitivity), with a significant reduction in time to metamorphosis (TTM) when exposed to underwater reef sound with an intensity of 90 dB re 1 µPa and greater (100, 126 and 135 dB re 1 µPa). Megalopae of the mud crab, Austrohelice crassa, which settle in soft sediment habitats, exhibited no response to any of the underwater reef sound levels. All reef associated species exposed to sound levels from an unfavourable settlement habitat showed no significant change in TTM, even at intensities that were similar to their preferred reef sound for which reductions in TTM were observed. These results indicated that megalopae were able to discern and respond selectively to habitat-specific acoustic cues. The settlement and metamorphosis behavioural response thresholds to levels of underwater reef sound determined in the current study of four species of crabs, enables preliminary estimation of the spatial range at which an acoustic settlement cue may be operating, from 5 m to 40 km depending on the species. Overall, these results indicate that underwater sound is likely to play a major role in influencing the spatial patterns of settlement of coastal crab species

    Use of a thermal battery with a heat pump for low temperature electric vehicle operation

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    Below 10°C, electric vehicles suffer from reduced range, which can be as severe as a 70% reduction (at -26°C). This is due to reduced battery performance at low temperatures and increased cabin heating demand. Heat pumps have been shown to have good steady state performance, but suffer slow and inefficient transients, while thermal storage has been shown to provide large heat flows and reduced warm up times, but space for such thermal storage is limited. Here a heat pump is combined with an optimally designed thermal battery and the simulated results are presented with improvements to energy consumption demonstrated

    Adaptive Avoidance of Reef Noise

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    Auditory information is widely used throughout the animal kingdom in both terrestrial and aquatic environments. Some marine species are dependent on reefs for adult survival and reproduction, and are known to use reef noise to guide orientation towards suitable habitat. Many others that forage in food-rich inshore waters would, however, benefit from avoiding the high density of predators resident on reefs, but nothing is known about whether acoustic cues are used in this context. By analysing a sample of nearly 700,000 crustaceans, caught during experimental playbacks in light traps in the Great Barrier Reef lagoon, we demonstrate an auditory capability in a broad suite of previously neglected taxa, and provide the first evidence in any marine organisms that reef noise can act as a deterrent. In contrast to the larvae of species that require reef habitat for future success, which showed an attraction to broadcasted reef noise, taxa with a pelagic or nocturnally emergent lifestyle actively avoided it. Our results suggest that a far greater range of invertebrate taxa than previously thought can respond to acoustic cues, emphasising yet further the potential negative impact of globally increasing levels of underwater anthropogenic noise

    'The palliative care ambulance' : a qualitative study of patient and caregiver perspectives of an ambulance service

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    Background: The need for home-based palliative care is accelerating internationally. At the same time, health systems face increased complexity, funding constraints and global shortages in the healthcare workforce. As such, ambulance services are increasingly tasked with providing palliative care. Where paramedics with additional training in palliative care have been integrated into models of care, evaluations have been largely positive. Studies of patient and family carer experiences of paramedic involvement, however, are limited. Aim: To explore patient and family caregiver experiences of paramedics’ contribution to palliative care at home. Design: Qualitative interview study. We analysed data within a social constructionist epistemology using reflexive thematic analysis. Setting/participants: Participants receiving specialist palliative care in the community of a metropolitan city of Australia who requested an ambulance between January and August 2018, inclusive. Results: Participants considered paramedics with expertise and experience in palliative care as an extension of the specialist community palliative care team and held them in high regard. Participants highlighted the importance of: critical palliative care at home and a timely, responsive approach; person-centred paramedics; as well as safety and security. Conclusion: Patients and carers feel safe and secure when they know that highly responsive skilled professional support is available when an unexpected problem or sudden change arises, especially out-of-hours, and that support is delivered in an empathic and person-centred manner

    Optimisation of direct battery thermal management for EVs operating in low-temperature climates

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    Electric vehicles (EVs) experience a range reduction at low temperatures caused by the impact of cabin heating and a reduction in lithium ion performance. Heat pump equipped vehicles have been shown to reduce heating ventilation and air conditioning (HVAC) consumption and improve low ambient temperature range. Heating the electric battery, to improve its low temperature performance, leads to a reduction in heat availability for the cabin. In this paper, dynamic programming is used to find the optimal battery heating trajectory which can optimise the vehicle’s control for either cabin comfort or battery performance and, therefore, range. Using the strategy proposed in this research, a 6.2% increase in range compared to no battery heating and 5.5% increase in thermal comfort compared to full battery heating was achieved at an ambient temperature at −7 ∘C

    Intramedullary Threaded Nail Fixation of Distal Ulnar Fractures: The Surgical Technique and Case Series

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    BACKGROUND: To describe the surgical technique of non-compressive intramedullary threaded nail (IMTN) fixation of distal ulnar neck fractures and present the clinical and radiographic outcomes of four patients treated with this novel technique. METHODS: At a single Level 1 Trauma Center, a retrospective review was conducted for patients with distal ulnar neck fractures treated with retrograde IMTN between 2022 and 2024. Exclusion criteria included inadequate follow-up. A single surgeon performed all procedures using percutaneous retrograde IMTN fixation through the central disc of the triangular fibrocartilage complex (TFCC). Patients initiated a range of motion (ROM) protocol two weeks post-operatively. Post-operative radiographic images were used to calculate the ratio of IMTN diameter to the distal ulnar medullary isthmus diameter proximal to the fracture site. Radiographic changes in displacement, angulation, and ulnar variance were calculated between the first and last follow-up radiographs. Functional outcomes including grip strength and ROM were collected. RESULTS: Four patients with distal ulnar neck fractures were treated with retrograde IMTN between 2022 and 2024. They were followed for a minimum of three months post-operatively. All were female with an average age of 65 years. All distal ulna fractures were associated with operatively treated intraarticular distal radius fractures. All patients were treated with 75 mm length and 4.5 mm diameter IMTNs. IMTN-to-Isthmus ratio was greater than 60% in all cases. Average radiographic displacement and angulation were unchanged at the final follow-up. The average ulnar variance increased by 1.2 mm. At the final follow-up, there were no post-operative complications. No cases demonstrated ulnar-sided wrist pain, nonunion, or required revision surgery. CONCLUSIONS: Retrograde IMTN fixation is a novel surgical technique for the treatment of distal ulnar neck fractures. We found limited but promising post-operative radiographic and functional outcomes in our patients without reported ulnar-sided wrist pain, nonunion, or need for hardware removal

    Distribution of Palinuridae and Scyllaridae phyllosoma larvae within the East Australian Current: a climate change hot spot

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    Many marine species are predicted to shift their ranges poleward due to rising ocean temperatures driven by climate change. For benthic marine species with pelagic larval stages, poleward range shifts are often facilitated through pelagic larval transport via western boundary currents (WBC). By surveying pelagic larval distributions within WBCs, species advected poleward of their known distributions can be identified and monitored. Palinurid and scyllarid lobster larvae (phyllosoma) have long pelagic larval durations, providing high potential for poleward advection. We surveyed spatial distribution of phyllosoma within the western-boundary East Australian Current. Due to difficulties morphologically identifying phyllosoma, we tested the utility of molecular identification using cytochrome c oxidase I (COI). From COI sequences of 56 phyllosoma and one postlarva, 65% of sequences consisted of good-quality mitochondrial DNA. Across water types sampled, scyllarid phyllosoma exhibited relatively homogeneous distribution, whereas palinurid phyllosoma exhibited heterogeneous distribution with greatest abundance inside a warm core eddy on the south coast of eastern Australia. Two tropical and one subtropical palinurid species were detected ~75–1800 km to the south or south-west of their known species distribution. Our results indicate tropical lobster species are reaching temperate regions, providing these species the opportunity to establish in temperate regions if or when environmental conditions become amenable to settlement

    Outcomes Following Surgical Fixation of Upper Extremity Fractures in Patients with Chronic Kidney Disease

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    Purpose: Moderate to severe (stage III-IV) chronic kidney disease (CKD) and end stage renal disease (ESRD) have been shown to be independent risk factors for sustaining a fragility fracture. High rates of complications and mortality are associated with fracture fixation in patients with CKD, but existing literature is limited. It is unknown how CKD stage III-IV or ESRD affects outcomes in upper-extremity fractures. We hypothesize that patients with CKD stage III-IV or ESRD will have high complication rates after surgical fixation of upper extremity fractures. Methods: We identified all patients between 2008 and 2018 who underwent operative fixation of an upper extremity fracture proximal to the distal radius with a diagnosis of CKD stage III-IV or ESRD at the time of injury. Those with an acute kidney injury at the time of injury or a history of a kidney transplant were excluded. Demographics, medical complications, and surgical complications were collected retrospectively. Data on readmissions within 90 days and mortality within 1 year were also collected. Results: Thirty-five patients were identified. Three patients had ESRD. Fractures included two clavicle, twelve proximal humerus, one humeral shaft, ten distal humerus, five olecranon, two ulnar shaft, one radial shaft, and two both-bone forearm fractures. In total, 91.4% of fractures were closed injuries. Surgical complications occurred in 40% of patients. The reoperation rate was 11.4%, and all cases of reoperation involved hardware removal. The all-cause 90-day readmission rate was 34.3%. The 1-year mortality rate was 8.6%. Conclusions: Surgical complications occurred in 40% of patients with CKD stage III-IV or ESRD who underwent fixation for an upper extremity fracture. It is important to counsel these patients regarding their high risk for complications. Further research is needed to investigate and identify how to mitigate risk. Type of study/level of evidence: Prognostic IV

    Outcomes Following Surgical Fixation of Distal Radius Fractures in Patients With Chronic Kidney Disease

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    Purpose: Moderate-to-severe chronic kidney disease (CKD, stages III-IV) and end-stage renal disease (ESRD or CKD stage V) are known to be independent risk factors for fragility fracture. Altered bone and mineral metabolism contributes to greater complications and mortality rates in the setting of fractures, although most existing literature is limited to hip fractures. We hypothesized that patients with moderate-to-severe CKD or ESRD would have greater complication rates after surgical treatment of distal radius fractures compared with those without CKD. Methods: We retrospectively identified all patients at a level 1 trauma center between 2008 and 2018 who had a diagnosis of stage III-IV CKD or ESRD at the time of operative fixation of a distal radius fracture. We recorded demographic data, comorbidities, and surgical complications. Data for readmissions within 90 days and 1-year mortality were collected. A 2:1 sex-matched control group without CKD who underwent distal radius fixation was selected for comparison, with age-adjusted analysis. Results: A total of 32 patients with CKD (78.1% CKD stage III/IV, 21.9% ESRD) and 62 without CKD were identified. The mean age was 67 ± 12 years in the CKD group and 55 ± 15 years in the control group. The CKD group had a higher Charlson Comorbidity Index (5.7 vs 2.0). Surgical complication rate in the CKD group was 12.5% (12.0% CKD III/IV; 14.3% ESRD). Neither early nor late surgical complication rates were statistically different from those in patients without CKD. Reoperation rate as well as 30- and 90-day readmission rates were similar between groups. Overall, 1-year mortality was greater in the CKD group (9.4% vs 0%). Conclusions: Surgical complications and readmission rates are similar in patients with and without CKD after distal radius fracture fixation. However, 1-year mortality rate is significantly higher after distal radius fixation in patients with moderate-to-severe CKD or ESRD. Type of study/level of evidence: Prognostic IIIa

    Metastable aluminium atoms floating on the surface of helium nanodroplets

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    Metal atoms have proved to be sensitive probes of the properties of superfluid helium nanodroplets. To date, all experiments on the doping of helium droplets have concentrated on the attachment of metal atoms in their ground electronic states. Here we report the first examples of metal atoms in excited states becoming attached to helium nanodroplets. The atoms in question are aluminium and they have been generated by laser ablation in a metastable quartet state, which attaches to and remains on the surface of helium droplets. Evidence for a surface location comes from electronic spectra, which consist of very narrow absorption profiles that show very small spectral shifts. Supporting ab initio calculations show there to be an energy incentive for a metastable Al atom to remain on the surface of a helium droplet rather than move to the interior. The results suggest that helium droplets may provide a method for the capture and transport of metastable excited atomic and molecular species
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