A new direction for differentiating animal activity based on measuring angular velocity about the yaw axis

The use of animal-attached data loggers to quantify animal movement has increased in popularity and application in recent years. High-resolution tri-axial acceleration and magnetometry measurements have been fundamental in elucidating fine-scale animal movements, providing information on posture, traveling speed, energy expenditure, and associated behavioral patterns. Heading is a key variable obtained from the tandem use of magnetometers and accelerometers, although few field investigations have explored fine-scale changes in heading to elucidate differences in animal activity (beyond the notable exceptions of dead-reckoning). This paper provides an overview of the value and use of animal heading and a prime derivative, angular velocity about the yaw axis, as an important element for assessing activity extent with potential to allude to behaviors, using “free-ranging” Loggerhead turtles (Caretta caretta) as a model species. We also demonstrate the value of yaw rotation for assessing activity extent, which varies over the time scales considered and show that various scales of body rotation, particularly rate of change of yaw, can help resolve differences between fine-scale behavior-specific movements. For example, oscillating yaw movements about a central point of the body's arc implies bouts of foraging, while unusual circling behavior, indicative of conspecific interactions, could be identified from complete revolutions of the longitudinal axis. We believe this approach should help identification of behaviors and “space-state” approaches to enhance our interpretation of behavior-based movements, particularly in scenarios where acceleration metrics have limited value, such as for slow-moving animals

Activity of loggerhead turtles during the U-shaped dive: insights using angular velocity metrics

Understanding the behavioural ecology of endangered taxa can inform conservation strategies. The activity budgets of the loggerhead turtle Caretta caretta are still poorly understood because many tracking methods show only horizontal displacement and ignore dives and associated behaviours. However, time-depth recorders have enabled researchers to identify flat, U-shaped dives (or type 1a dives) and these are conventionally labelled as resting dives on the seabed because they involve no vertical displacement of the animal. Video- and acceleration-based studies have demonstrated this is not always true. Focusing on sea turtles nesting on the Cabo Verde archipelago, we describe a new metric derived from magnetometer data, absolute angular velocity, that integrates indices of angular rotation in the horizontal plane to infer activity. Using this metric, we evaluated the variation in putative resting behaviours during the bottom phase of type 1a dives for 5 individuals over 13 to 17 d at sea during a single inter-nesting interval (over 75 turtle d in total). We defined absolute resting within the bottom phase of type 1a dives as periods with no discernible acceleration or angular movement. Whilst absolute resting constituted a significant proportion of each turtle’s time budget for this 1a dive type, turtles allocated 16−38% of their bottom time to activity, with many dives being episodic, comprised of intermittent bouts of rest and rotational activity. This implies that previously considered resting behaviours are complex and need to be accounted for in energy budgets, particularly since energy budgets may impact conservation strategies. © The authors 2021. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are unrestricted. Authors and original publication must be credite

Behavioral Biomarkers for Animal Health: A Case Study Using Animal-Attached Technology on Loggerhead Turtles

Vertebrates are recognized as sentient beings. Consequently, urgent priority is now being given to understanding the needs and maximizing the welfare of animals under human care. The general health of animals is most commonly determined by physiological indices e.g., blood sampling, but may also be assessed by documenting behavior. Physiological health assessments, although powerful, may be stressful for animals, time-consuming and costly, while assessments of behavior can also be time-consuming, subject to bias and suffer from a poorly defined link between behavior and health. However, behavior is recognized as having the potential to code for stress and well-being and could, therefore, be used as an indicator of health, particularly if the process of quantifying behavior could be objective, formalized and streamlined to be time efficient. This study used Daily Diaries (DDs) (motion-sensitive tags containing tri-axial accelerometers and magnetometers), to examine aspects of the behavior of bycaught loggerhead turtles, Caretta caretta in various states of health. Although sample size limited statistical analysis, significant behavioral differences (in terms of activity level and turn rate) were found between “healthy” turtles and those with external injuries to the flippers and carapace. Furthermore, data visualization (spherical plots) clearly showed atypical orientation behavior in individuals suffering gas emboli and intestinal gas, without complex data analysis. Consequently, we propose that the use of motion-sensitive tags could aid diagnosis and inform follow-up treatment, thus facilitating the rehabilitation process. This is particularly relevant given the numerous rehabilitation programs for bycatch sea turtles in operation. In time, tag-derived behavioral biomarkers, TDBBs for health could be established for other species with more complex behavioral repertoires such as cetaceans and pinnipeds which also require rehabilitation and release. Furthermore, motion-sensitive data from animals under human care and wild conspecifics could be compared in order to define a set of objective behavioral states (including activity levels) for numerous species housed in zoos and aquaria and/or wild species to help maximize their welfare

Estimates for energy expenditure in free‐living animals using acceleration proxies; a reappraisal

It is fundamentally important for many animal ecologists to quantify the costs of animal activities, although it is not straightforward to do so. The recording of triaxial acceleration by animal-attached devices has been proposed as a way forward for this, with the specific suggestion that dynamic body acceleration (DBA) be used as a proxy for movement-based power. Dynamic body acceleration has now been validated frequently, both in the laboratory and in the field, although the literature still shows that some aspects of DBA theory and practice are misunderstood. Here, we examine the theory behind DBA and employ modelling approaches to assess factors that affect the link between DBA and energy expenditure, from the deployment of the tag, through to the calibration of DBA with energy use in laboratory and field settings. Using data from a range of species and movement modes, we illustrate that vectorial and additive DBA metrics are proportional to each other. Either can be used as a proxy for energy and summed to estimate total energy expended over a given period, or divided by time to give a proxy for movement-related metabolic power. Nonetheless, we highlight how the ability of DBA to predict metabolic rate declines as the contribution of non-movement-related factors, such as heat production, increases. Overall, DBA seems to be a substantive proxy for movement-based power but consideration of other movement-related metrics, such as the static body acceleration and the rate of change of body pitch and roll, may enable researchers to refine movement-based metabolic costs, particularly in animals where movement is not characterized by marked changes in body acceleration

Controllable Dry Adhesion due to Surface Micro-Defect Patterning

Robotic automation continues to develop and is constantly in need for new gripping devices. Devices are needed to handle small delicate objects for pick and place applications. Traditional rigid grippers have difficulty adapting to varying objects, and pneumatic grippers require bulky pumps and compressed air. Dry adhesion devices can remove the need for rigid components or pneumatics by relying on adhesion as the main method to pick up and manipulate objects. Tunable dry adhesion refers to the ability of controlling adhesion, increasing and decreasing it as the task requires. Research continues to develop devices that offer the highest tunability ratio. Based on a subsurface stiffness modulating device proposed by Shan et al. a novel method for increase adhesion in the normal direction is proposed, using circular defects on the adhering surface of a PDMS (polydimethysiloxane) post. The fabrication process included photolithography and molding which produced high resolution defects with high placement accuracy. The proposed patterns resulted in an increased adhesion, and for certain patterns, an increase of roughly 40%, compared to a flat PDMS post. Simulations helped explain the point of failure observed in the experimental results and provided some clarification to the increase of adhesion. Contact splitting and other mechanics offer explanations for the increase of adhesion and work continues to be done to further identify the mechanics involved. Defect patterning can be paired with subsurface stiffness modulation, previously studied by the Shan Research Group to increase the tunability ratio and develop new devices for pick and place automation

Indigenous small enterprise development : implications for policy

There are a number of important ways in which economic independence for Indigenous Australians can be enhanced and the economic development of their communities promoted. An important avenue will lie in the establishment of small business enterprises. The Royal Commission into Aboriginal Deaths in Custody made valuable proposals about the means by which government policies and programs might be structured to maximise the opportunities for improving the economic situation of Indigenous people. This included the identification of a number of small business sectors seen to be important in promoting Indigenous economic development. Many of these proposals have remained dormant. Within this context an initial requirement is for a better understanding of the main determinants of Indigenous labour force behaviour at the local level. A main purpose of this paper therefore is to investigate, using Population Census data, the Indigenous labour force outcomes of a number of small, relatively remote regions within the Northern Territory of Australia

The importance of Indigenous educational outcomes to small enterprise development within remote Indigenous communities of Northern Australia

This paper assesses the extent to which the education system in Australia has produced outcomes likely to facilitate the development of an entrepreneurial culture for Indigenous Australians. Data from the 1991 and 1996 censuses indicate that Indigenous Australians are more likely than Non-Indigenous to leave school at an early age. Their level of attendance at post-secondary educational institutions is also substantially lower. Young Indigenous people are less likely to hold a qualification than their Non-Indigenous counterparts. Such outcomes are supported by field research in remote communities in the Northern Territory, which indicates that the skills required to manage and operate a small business are extremely scarce. This situation, and the poor educational outcomes that contribute to it, is one of the most important constraints upon the development of Indigenous owned and operated small businesses in remote areas, with important implications for economic and human development. The paper suggests a number of reasons why this situation exists. It also proposes a number of policy changes designed to increase the number of Indigenous small business owner-managers, by enhancing the educational outcomes of Indigenous young people

Modeling and evaluation of magnetic fluid deformable mirror with dual-layer actuators

In this paper, a rectangular magnetic fluid deformable mirror (MFDM) with dual-layer actuators is proposed, which is designed to improve the correction performance for full-order aberrations. Compared with the conventional adaptive optics system that uses two mirrors to configure as a woofer–tweeter system, the proposed MFDM combines the two mirrors into one by using a two-layer layout design of the actuators. Firstly, based on the governing equations of the magnetic fluid, derived from the principles of conservation of fluid mass and magnetic field, the dynamics model of surface deflection of the MFDM is analyzed in Cartesian coordinates under the boundary conditions of the magnetic field and the kinematic conditions of magnetic fluid. Then, the analytical solutions of the surface movement of the mirror subject to the applied currents in the electromagnetic coils are obtained by properly separating the variables with truncated model numbers. Finally, the experimental results based on a fabricated prototype square MFDM show the effectiveness of modeling and the correction performance of the mirror for the full-order aberrations

Modelling intramolecular electron transfer reactions in cytochromes and in photosynthetic bacteria reaction centres

Electron transfer rates within protein systems with various donor acceptor distances, reaction-free energies and temperatures, are calculated as the product of an electron tunneling probability and a nuclear distortion activation term. The electronic factor is given by the frequency of electronic motion in the donor, the donor electron energy, the donor-acceptor distance and the protein refractive index. Nuclear distortion is obtained from bond lengths, force constants and bond orders of the co-factor bonds involved in the reaction coordinate. The nuclear factor is calculated according to thermal activation and nuclear tunneling mechanisms. The calculation of distance, free-energy and temperature dependence of photoinduced-intraprotein electron transfer rates in Ru/Zn-modified cytochromes and myoglobins does not rely on fitting unknown parameters to kinetic data and is in good agreement with the experiment. Systems with reduced masses lower than 100 a.m.u. may undergo sizable nuclear tunneling at room temperature.http://www.sciencedirect.com/science/article/B6TGY-3VGT0HT-1M/1/dcf47d6786a1ab78c9d8f701f459147