Search

Introduction: A disproportionate number of mental health presentations to emergency services are made by frequent presenters. No current consensus definition of a frequent presenter exists. Using a statewide population-based ambulance database, this study (i) applied previous statistical methods to determine thresholds for frequent presenters, (ii) explored characteristics of the identified frequent presenter groups compared to non-frequent presenters and (iii) assessed the reliability of these methods in predicting continued frequent presenter status over time. Methods: Statistical methods utilised in previous studies to identify frequent presenters were applied to all ambulance attendances for mental health symptoms, self-harm and alcohol and other drug issues between 1 January 2017 and 31 December 2020 in Victoria, Australia. Differences in characteristics between identified frequent and non-frequent presenter groups were determined by logistic regression analysis. The consistency of agreement of frequent presenter status over time was assessed using intraclass correlation coefficients. Results: Thresholds for frequent presenters ranged from a mean of 5 to 39 attendances per calendar year, with groups differing in size, service use and characteristics. Compared to non-frequent presenters, frequent presenters had greater odds of being female, presenting with self-harm, experiencing social disadvantage or housing issues, involving police co-attendance and being transported to hospital. All frequent presenter definitions had poor reliability in predicting ongoing frequent presentations over time. Conclusion: A range of methods can define frequent presenters according to thresholds of yearly service use. Reasons for identifying frequent presenters may influence the method chosen. Future studies should explore definitions that capture the dynamic nature of presentations by this group. [ABSTRACT FROM AUTHOR]

We present a mixed integer programming model for prioritizing fuel treatments within a landscape fuel break network to maximize protection against wildfires, measured by the total fire size reduction or the sum of Wildland Urban Interface areas avoided from burning. This model uses a large dataset of simulated wildfires in a large landscape to inform fuel break treatment decisions. Its mathematical formulation is concise and computationally efficient, allowing for customization and expansion to address more complex and challenging fuel break management problems in diverse landscapes. We constructed test cases for Southern California of the United States to understand model outcomes across a wide range of fire and fuel management scenarios. Results suggest optimal fuel treatment layouts within the Southern California's fuel break network responding to various model assumptions, which offer insights for regional fuel break planning. Comparative tests between the proposed optimization model and a rule-based simulation approach indicate that the optimization model can provide significantly better solutions within reasonable solving times, highlighting its potential to support fuel break management and planning decisions. [ABSTRACT FROM AUTHOR]

Arboreal locomotion is precarious and places multiple challenges upon stability. Studies have shown that captive primates respond to narrower and steeper supports by flexing limb joints and adopting a compliant gait. We tested whether these same kinematic responses are adopted by wild primates freely ranging over a variety of supports in their natural habitats. We recorded five species of platyrrhines, five species of catarrhines, and four species of strepsirrhines with modified GoPro cameras and used remote measurement to quantify substrate characteristics. Video images were imported into ImageJ to measure the angular kinematics of limb joints during quadrupedal locomotion on a variety of arboreal supports. We statistically tested for associations between joint posture and substrate characteristics, and then disentangled the influence of phylogeny and substrate on limb joint kinematics using variation partitioning and redundancy analysis. Our results partially confirm previous kinematic studies and suggest variation in support orientation, more than diameter or compliance, influences quadrupedal gait kinematics. Phylogenetic relatedness explained more variation in the data than substrate properties. This suggests primates either prospectively choose relatively 'safe' substrates for locomotion, or that they possess locomotor adaptations independent of limb joint kinematics per se to overcome the challenges of the precarious arboreal environment. [ABSTRACT FROM AUTHOR]

Several studies comparing primate locomotion under lab versus field conditions have shown the importance of implementing both types of studies, as each has their advantages and disadvantages. However, three‐dimensional (3D) motion capture of primates has been challenging under natural conditions. In this study, we provide a detailed protocol on how to collect 3D biomechanical data on primate leaping in their natural habitat that can be widely implemented. To record primate locomotion in the dense forest we use modified GoPro Hero Black cameras with zoom lenses that can easily be carried around and set up on tripods. We outline details on how to obtain camera calibrations at greater heights and how to process the collected data using the MATLAB camera calibration app and the motion tracking software DLTdv8a. We further developed a new MATLAB application "WildLeap3D" to generate biomechanical performance metrics from the derived x, y, z coordinates of the leaps. We provide details on how to collect data on support diameter, compliance, and orientation, and combine these with the jumps to study locomotor performance in an ecological context. We successfully reconstructed leaps of wild primates in the 3D space under natural conditions and provided data on four representative leaps. We provide exemplar data on primate velocity and acceleration during a leap and show how our protocol can be used to analyze segmental kinematics. This study will help to make motion capture of freely moving animals more accessible and help further our knowledge about animal locomotion and movement. Research Highlights: The workflow and equipment described make motion capture of wild animals more accessible, facilitating important studies. We provide four example leaps of wild primates in different species, variable environments and several types of jumps. [ABSTRACT FROM AUTHOR]

Objectives: Despite qualitative observations of wild primates pumping branches before leaping across gaps in the canopy, most studies have suggested that support compliance increases the energetic cost of arboreal leaping, thus limiting leaping performance. In this study, we quantified branch pumping behavior and tree swaying in wild primates to test the hypothesis that these behaviors improve leaping performance. Materials and Methods: We recorded wild colobine monkeys crossing gaps in the canopy and quantitatively tracked the kinematics of both the monkey and the compliant support during behavioral sequences. We also empirically measured the compliance of a sample of locomotor supports in the monkeys' natural habitat, allowing us to quantify the resonant properties of substrates used during leaping. Results: Analyses of three recordings show that adult red colobus monkeys (Piliocolobus tephrosceles) use branch compliance to their advantage by actively pumping branches before leaping, augmenting their vertical velocity at take‐off. Quantitative modeling of branch resonance periods, based on empirical measurements of support compliance, suggests that monkeys specifically employed branch pumping on relatively thin branches with protracted periods of oscillation. Finally, an additional four recordings show that both red colobus and black and white colobus monkeys (Colobus guereza) utilize tree swaying to cross large gaps, augmenting horizontal velocity at take‐off. Discussion: This deliberate branch manipulation to produce a mechanical effect for stronger propulsion is consistent with the framework of instrumental problem‐solving. To our knowledge, this is the first study of wild primates which quantitatively shows how compliant branches can be used advantageously to augment locomotor performance. [ABSTRACT FROM AUTHOR]