Stephan Schwarzinger

Skull shape of a widely distributed, endangered marsupial reveals little evidence of local adaptation between fragmented populations

Publisher: Wiley

Date: 18-08-2020

DOI: 10.1002/ECE3.6593

Cooperation Improves Success during Intergroup Competition: An Analysis Using Data from Professional Soccer Tournaments

Publisher: Public Library of Science (PLoS)

Date: 27-08-2015

DOI: 10.1371/JOURNAL.PONE.0136503

Multivariate analyses of individual variation in soccer skill as a tool for talent identification and development: utilising evolutionary theory in sports science

Publisher: Informa UK Limited

Date: 26-02-2016

DOI: 10.1080/02640414.2016.1151544

Abstract: The development of a comprehensive protocol for quantifying soccer-specific skill could markedly improve both talent identification and development. Surprisingly, most protocols for talent identification in soccer still focus on the more generic athletic attributes of team sports, such as speed, strength, agility and endurance, rather than on a player's technical skills. We used a multivariate methodology borrowed from evolutionary analyses of adaptation to develop our quantitative assessment of in idual soccer-specific skill. We tested the performance of 40 in idual academy-level players in eight different soccer-specific tasks across an age range of 13-18 years old. We first quantified the repeatability of each skill performance then explored the effects of age on soccer-specific skill, correlations between each of the pairs of skill tasks independent of age, and finally developed an in idual metric of overall skill performance that could be easily used by coaches. All of our measured traits were highly repeatable when assessed over a short period and we found that an in idual's overall skill - as well as their performance in their best task - was strongly positively correlated with age. Most importantly, our study established a simple but comprehensive methodology for assessing skill performance in soccer players, thus allowing coaches to rapidly assess the relative abilities of their players, identify promising youths and work on eliminating skill deficits in players.

Multidimensional analyses of physical performance reveal a size-dependent trade-off between suites of traits

Publisher: Wiley

Date: 09-05-2018

DOI: 10.1111/1365-2435.13115

Potential bias in NMR relaxation data introduced by peak intensity analysis and curve fitting methods

Publisher: Springer Science and Business Media LLC

Date: 2001

DOI: 10.1023/A:1011966718826

Abstract: We present an evaluation of the accuracy and precision of relaxation rates calculated using a variety of methods, applied to data sets obtained for several very different protein systems. We show that common methods of data evaluation, such as the determination of peak heights and peak volumes, may be subject to bias, giving incorrect values for quantities such as R1 and R2. For ex le, one common method of peak-height determination, using a search routine to obtain the peak-height maximum in successive spectra, may be a source of significant systematic error in the relaxation rate. The alternative use of peak volumes or of a fixed coordinate position for the peak height in successive spectra gives more accurate results, particularly in cases where the signal/noise is low, but these methods have inherent problems of their own. For ex le, volumes are difficult to quantitate for overlapped peaks. We show that with any method of s ling the peak intensity, the choice of a 2- or 3-parameter equation to fit the exponential relaxation decay curves can dramatically affect both the accuracy and precision of the calculated relaxation rates. In general, a 2-parameter fit of relaxation decay curves is preferable. However, for very low intensity peaks a 3 parameter fit may be more appropriate.

Optimal running speeds when there is a trade-off between speed and the probability of mistakes

Publisher: Wiley

Date: 13-06-2017

DOI: 10.1111/1365-2435.12902

Conformational and Dynamic Characterization of the Molten Globule State of an Apomyoglobin Mutant with an Altered Folding Pathway

Publisher: American Chemical Society (ACS)

Date: 07-11-2001

DOI: 10.1021/BI011500N

Abstract: Kinetic and equilibrium studies of apomyoglobin folding pathways and intermediates have provided important insights into the mechanism of protein folding. To investigate the role of intrinsic helical propensities in the apomyoglobin folding process, a mutant has been prepared in which Asn132 and Glu136 have been substituted with glycine to destabilize the H helix. The structure and dynamics of the equilibrium molten globule state formed at pH 4.1 have been examined using NMR spectroscopy. Deviations of backbone (13)C(alpha) and (13)CO chemical shifts from random coil values reveal high populations of helical structure in the A and G helix regions and in part of the B helix. However, the H helix is significantly destabilized compared to the wild-type molten globule. Heteronuclear [(1)H]-(15)N NOEs show that, although the polypeptide backbone in the H helix region is more flexible than in the wild-type protein, its motions are restricted by transient hydrophobic interactions with the molten globule core. Quench flow hydrogen exchange measurements reveal stable helical structure in the A and G helices and part of the B helix in the burst phase kinetic intermediate and confirm that the H helix is largely unstructured. Stabilization of structure in the H helix occurs during the slow folding phases, in synchrony with the C and E helices and the CD region. The kinetic and equilibrium molten globule intermediates formed by N132G/E136G are similar in structure. Although both the wild-type apomyoglobin and the mutant fold via compact helical intermediates, the structures of the intermediates and consequently the detailed folding pathways differ. Apomyoglobin is therefore capable of compensating for mutations by using alternative folding pathways within a common basic framework. Tertiary hydrophobic interactions appear to play an important role in the formation and stabilization of secondary structure in the H helix of the N132G/E136G mutant. These studies provide important insights into the interplay between secondary and tertiary structure formation in protein folding.

Rocky escarpment versus savanna woodlands: comparing diet and body condition as indicators of habitat quality for the endangered northern quoll (Dasyurus hallucatus)

Publisher: CSIRO Publishing

Date: 09-04-2021

DOI: 10.1071/WR20032

Abstract: Abstract Context Understanding what constitutes high-quality habitat for threatened species is critical for conservation management planning. The endangered northern quoll (Dasyurus hallucatus) has experienced an uneven range contraction among habitat types. Once common across multiple habitats of northern mainland Australia, declining populations have now contracted to rocky escarpments. Aim The island refuge of Groote Eylandt, Northern Territory, Australia, has not experienced the declines as seen on mainland Australia. Here, northern quolls persist in both rocky escarpment and savanna woodland, which provides a rare opportunity to investigate the habitat quality of rocky escarpments and savanna woodland for the northern quoll. Methods Northern quolls (n = 111) were trapped in both rocky escarpment (n = 61) and savanna woodland (n = 50) habitats before the breeding season (May). We conducted body condition assessment, scat analysis, and measured trophic niche breadth of in iduals occupying each habitat type. Key results Female quolls occupying rocky escarpments exhibited a lower body condition than did quolls occupying savanna woodland. Quolls from rocky escarpments consumed a significantly higher proportion of mammals and fed within a narrower dietary niche than did those occupying savanna woodland. Conclusions Quolls had adapted to the dietary resources available within each habitat type, suggesting that the lack of quolls in savanna woodland on the mainland is due to factors other than availability of dietary resources. Implications Groote Eylandt is of critical conservation significance, where high numbers of northern quolls exist in both rocky escarpment and savanna woodland habitats. For population viability on the mainland, managing threats such as feral predators and inappropriate fire regimes in savanna woodland, particularly those surrounding rocky escarpment, should be prioritised.

Moving in complex environments: a biomechanical analysis of locomotion on inclined and narrow substrates

Publisher: The Company of Biologists

Date: 2019

DOI: 10.1242/JEB.189654

Abstract: Characterisation of an organism's performance in different habitats provides insight into the conditions that allow it to survive and reproduce. In recent years, Northern quolls (Dasyurus hallucatus)—a medium-sized semi-arboreal marsupial native to northern Australia—have undergone significant population declines within open forest, woodland and riparian habitats, but less so in rocky areas. To help understand this decline, we quantified the biomechanical performance of wild Northern quolls as they ran up inclined narrow (13 mm pole) and inclined wide (90 mm platform) substrates. We predicted that quolls may possess biomechanical adaptations to increase stability on narrow surfaces, which are more common in rocky habitats. Our results display that quolls have some biomechanical characteristics consistent with a stability advantage on narrow surfaces. This includes the coupled use of limb pairs, as indicated via a decrease in footfall time, and an ability to produce corrective torques to counteract the toppling moments commonly encountered during gait on narrow surfaces. However, speed was constrained on narrow surfaces, and quolls did not adopt diagonal sequence gaits unlike true arboreal specialists such as primates. In comparison with key predators, such as cats and dogs, Northern quolls appear inferior in terrestrial environments but have a stability advantage at higher speeds on narrow supports. This may partially explain the heterogenous declines in Northern quoll populations among various habitats on mainland Australia.

Random coil chemical shifts in acidic 8 M urea: implementation of random coil shift data in NMRView.

Publisher: Springer Science and Business Media LLC

Date: 2000

DOI: 10.1023/A:1008386816521

Abstract: Studies of proteins unfolded in acid or chemical denaturant can help in unraveling events during the earliest phases of protein folding. In order for meaningful comparisons to be made of residual structure in unfolded states, it is necessary to use random coil chemical shifts that are valid for the experimental system under study. We present a set of random coil chemical shifts obtained for model peptides under experimental conditions used in studies of denatured proteins. This new set, together with previously published data sets, has been incorporated into a software interface for NMRView, allowing selection of the random coil data set that fits the experimental conditions best.

Structural characterization of partially folded intermediates of apomyoglobin H64F

Publisher: Wiley

Date: 02-2008

DOI: 10.1110/PS.073187208

Surface friction alters the agility of a small Australian marsupial

Publisher: The Company of Biologists

Date: 2018

DOI: 10.1242/JEB.172544

Abstract: Movement speed can underpin an animal's probability of success in ecological tasks. Prey often use agility to outmanoeuvre predators, however faster speeds increase inertia and reduce agility. Agility is also constrained by grip, as the foot must have sufficient friction with the ground to apply the forces required for turning. Consequently, ground surface should affect optimum turning speed. We tested the speed-agility trade-off in buff-footed antechinus (Antechinus mysticus) on two different surfaces. Antechinus used slower turning speeds over smaller turning radii on both surfaces, as predicted by the speed-agility trade-off. Slipping was 64% more likely on the low-friction surface, and had a higher probability of occurring the faster the antechinus were running before the turn. However, antechinus compensated for differences in surface friction by using slower pre-turn speeds as their amount of experience on the low-friction surface increased, which consequently reduced their probability of slipping. Conversely, on the high-friction surface, antechinus used faster pre-turn speeds in later trials, which had no effect on their probability of slipping. Overall, antechinus used larger turning radii (0.733 ± 0.062 vs 0.576 ± 0.051 m) and slower pre-turn (1.595 ± 0.058 vs 2.174 ± 0.050 ms-1) and turning speeds (1.649 ± 0.061 vs 2.01 ± 0.054 ms-1) on the low-friction surface. Our results demonstrate the interactive effect of surface friction and the speed-agility trade-off on speed choice. To predict wild animals’ movement speeds, future studies should examine the interactions between biomechanical trade-offs and terrain, and quantify the costs of motor mistakes in different ecological activities.

The influence of speed and size on avian terrestrial locomotor biomechanics: Predicting locomotion in extinct theropod dinosaurs

Publisher: Public Library of Science (PLoS)

Date: 21-02-2018

DOI: 10.1371/JOURNAL.PONE.0192172

Running faster causes disaster: Trade-offs between speed, manoeuvrability and motor control when running around corners in northern quolls (Dasyurus hallucatus)

Publisher: The Company of Biologists

Date: 02-2015

DOI: 10.1242/JEB.111682

Abstract: Movement speed is fundamental to all animal behaviour, yet no general framework exists for understanding why animals move at the speeds they do. Even during fitness-defining behaviours like running away from predators, an animal should select a speed that balances the benefits of high speed against the increased probability of mistakes. In this study, we explored this idea by quantifying trade-offs between speed, manoeuvrability and motor control in wild northern quolls (Dasyurus hallucatus) – a medium-sized carnivorous marsupial native to northern Australia. First, we quantified how running speed affected the probability of crashes when rounding corners of 45, 90 and 135 deg. We found that the faster an in idual approached a turn, the higher the probability that they would crash, and these risks were greater when negotiating tighter turns. To avoid crashes, quolls modulated their running speed when they moved through turns of varying angles. Average speed for quolls when sprinting along a straight path was around 4.5 m s−1 but this decreased linearly to speeds of around 1.5 m s−1 when running through 135 deg turns. Finally, we explored how an in idual's morphology affects their manoeuvrability. We found that in iduals with larger relative foot sizes were more manoeuvrable than in iduals with smaller relative foot sizes. Thus, movement speed, even during extreme situations like escaping predation, should be based on a compromise between high speed, manoeuvrability and motor control. We advocate that optimal – rather than maximal – performance capabilities underlie fitness-defining behaviours such as escaping predators and capturing prey.

Sequence-Dependent Correction of Random Coil NMR Chemical Shifts

Publisher: American Chemical Society (ACS)

Date: 06-03-2001

DOI: 10.1021/JA003760I

Abstract: Random coil chemical shifts are commonly used to detect secondary structure elements in proteins in chemical shift index calculations. While this technique is very reliable for folded proteins, application to unfolded proteins reveals significant deviations from measured random coil shifts for certain nuclei. While some of these deviations can be ascribed to residual structure in the unfolded protein, others are clearly caused by local sequence effects. In particular, the amide nitrogen, amide proton, and carbonyl carbon chemical shifts are highly sensitive to the local amino acid sequence. We present a detailed, quantitative analysis of the effect of the 20 naturally occurring amino acids on the random coil shifts of (15)N(H), (1)H(N), and (13)CO resonances of neighboring residues, utilizing complete resonance assignments for a set of five-residue peptides Ac-G-G-X-G-G-NH(2). The work includes a validation of the concepts used to derive sequence-dependent correction factors for random coil chemical shifts, and a comprehensive tabulation of sequence-dependent correction factors that can be applied for amino acids up to two residues from a given position. This new set of correction factors will have important applications to folded proteins as well as to short, unstructured peptides and unfolded proteins.

Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds

Publisher: The Royal Society

Date: 07-2017

DOI: 10.1098/RSIF.2017.0276

Abstract: How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width—the mediolateral (transverse) distance between successive footfalls—was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods ( p 0.001), as well as the five tallest bird species studied ( p 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk–run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history.

Does individual quality mask the detection of performance trade-offs? A test using analyses of human physical performance

Publisher: The Company of Biologists

Date: 15-02-2014

DOI: 10.1242/JEB.092056

Abstract: Why are performance trade-offs so rarely detected in animals when their underlying physiological basis seems so intuitive? One possibility is that in idual variation in health, fitness, nutrition, development or genetics, or 'in idual quality', makes some in iduals better or worse performers across all motor tasks. If this is the case, then correcting for in idual quality should reveal functional trade-offs that might otherwise be overlooked. We tested this idea by exploring trade-offs in maximum physical performance and motor skill function in semi-professional soccer players. We assessed in idual performance across five maximum 'athletic' tasks providing independent measures of power, stamina and speed, as well as five soccer-specific 'motor skill' tasks providing independent measures of foot control. We expected to find functional trade-offs between pairs of traits (e.g. endurance versus power/speed tasks or specialist-generalist performance) - but only after correcting for in idual quality. Analyses of standardised raw data found positive associations among several pairs of traits, but no evidence of performance trade-offs. Indeed, peak performance across a single athletic task (degree of specialisation) was positively associated with performance averaged across all other athletic tasks (generalist). However, after accounting for an in idual's overall quality, several functional trade-offs became evident. Within our quality-corrected data, 1500 m-speed (endurance) was negatively associated with squat time (power), jump distance (power) and agility speed - reflecting the expected speed-endurance trade-off and degree of specialisation was negatively associated with average performance across tasks. Taken together, our data support the idea that in idual variation in general quality can mask the detection of performance trade-offs at the whole-animal level. These results highlight the possibility that studies may spuriously conclude certain functional trade-offs are unimportant or non-existent when analyses that account for variation in general quality may reveal their cryptic presence.

Females prefer athletes, males fear the disadvantaged: different signals used in female choice and male competition have varied consequences

Publisher: The Royal Society

Date: 24-02-2010

DOI: 10.1098/RSPB.2009.2196

Abstract: The most commonly assumed cost for exaggerated male ornamentation is increased predation pressure owing to decreased locomotor performance or increased conspicuousness to predators. Despite its intuitive basis, the locomotor costs of male ornamentation are not well established. We tested the hypothesis that multiple male signals that are used independently during female choice and male competition could lead to varied locomotor costs. Multiple signals with varied costs could provide a more detailed indicator of overall male quality, as only the highest-quality in iduals could support all costs. To test this idea, we investigated the burst locomotor consequences of multiple ornaments for males of the pacific blue-eye ( Pseudomugil signifer ). We evaluated five competing models relating body size, ornament size and performance traits to field measures of dominance and attractiveness. Non-propulsive male fin ornaments used during male competition were different from those used in female choice. First dorsal fin length was the most important predictor of male attractiveness, while dominance was only associated with anal fin length. Furthermore, first dorsal fin length was positively correlated with swim speed, while anal fin length was negatively associated with speed. Our study shows that multiple male signals that are used independently during male competition and female choice also differ in their associated costs. This provides a mechanism for understanding why locomotor costs for exaggerated male ornamentation are not often empirically demonstrated.

Manganese contamination affects the motor performance of wild northern quolls (Dasyurus hallucatus)

Publisher: Elsevier BV

Date: 10-2018

DOI: 10.1016/J.ENVPOL.2018.03.087

Abstract: Neuromotor deficits are an important sign of manganese (Mn) toxicity in humans and laboratory animals. However, the impacts of Mn exposure on the motor function of wild animals remains largely unknown. Here, we assessed the impact of chronic exposure to Mn from active mining operations on Groote Eylandt, Australia on the motor function of the semi-arboreal northern quoll (Dasyurus hallucatus), an endangered species. The three motor tests conducted-maximum sprint speed on a straight run, manoeuvrability around a corner, and motor control on a balance beam-showed that elevated Mn body burden did not diminish performance of these traits. However, quolls with higher Mn body burden approached a corner at a significantly narrower range of speeds, due to a significantly lower maximum approach speed. Slower speeds approaching a turn may reduce success at catching prey and avoiding predators. Given that maximum sprint speed on a straight run was not affected by Mn body burden, but maximum speed entering a corner was, slower speeds approaching a turn may reflect compensation for otherwise impaired performance in the turn.

Improving sneaky-sex in a low oxygen environment: reproductive and physiological responses of male mosquito fish to chronic hypoxia

Publisher: The Company of Biologists

Date: 15-12-2006

DOI: 10.1242/JEB.02531

Abstract: Few studies have examined the adaptive significance of reversible acclimation responses. The aerobic performance and mating behaviour of the sexually coercive male eastern mosquito fish (Gambusia holbrooki)offers an excellent model system for testing the benefits of reversible acclimation responses to mating success. We exposed male mosquito fish to normoxic or hypoxic conditions for 4 weeks and tested their maximum sustained swimming performance and their ability to obtain coercive matings under both normoxic and hypoxic conditions. We predicted that hypoxia-acclimated males would possess greater swimming and mating performance in hypoxic conditions than normoxic-acclimated males, and vice versa when tested in normoxia. Supporting our predictions, we found the sustained swimming performance of male mosquito fish was greater in a hypoxic environment following long-term exposure to low partial pressures of oxygen. However, the benefits of acclimation responses to mating performance were dependent on whether they were tested in the presence or absence of male-male competition. In a non-competitive environment, male mosquito fish acclimated to hypoxic conditions spent a greater amount of time following females and obtained more copulations than normoxic-acclimated males when tested in low partial pressures of oxygen. When males were competed against each other for copulations, we found no influence of long-term exposure to different partial pressures of oxygen on mating behaviour. Thus, despite improvements in the aerobic capacity of male mosquito fish following long-term acclimation to hypoxic conditions, these benefits did not always manifest themselves in improved mating performance. This study represents one of the first experimental tests of the benefits of reversible acclimation responses, and indicates that the ecological significance of physiological plasticity may be more complicated than previously imagined.

Speed and maneuverability jointly determine escape success: Exploring the functional bases of escape performance using simulated games

Publisher: Oxford University Press (OUP)

Date: 31-07-2016

DOI: 10.1093/BEHECO/ARV080

Resting disparity in quoll semelparity: examining the sex-linked behaviours of wild roaming northern quolls ( Dasyurus hallucatus ) during breeding season

Publisher: The Royal Society

Date: 02-2023

DOI: 10.1098/RSOS.221180

Abstract: Semelparity is a breeding strategy whereby an in idual invests large amounts of resources into a single breeding season, leading to the death of the in idual. Male northern quolls ( Dasyurus hallucatus ) are the largest known mammal to experience a post-breeding die-off however, the cause of their death is unknown, dissimilar from causes in other semelparous dasyurids. To identify potential differences between male northern quolls that breed once, and females that can breed for up to four seasons, the behaviours, activity budgets, speeds and distances travelled were examined. Northern quolls were captured on Groote Eylandt off the coast of the Northern Territory, Australia, and were fitted with accelerometers. A machine learning algorithm (Self-organizing Map) was trained on more than 76 h of recorded footage of quoll behaviours and used to predict behaviours in 42 days of data from wild roaming quolls (7M : 6F). Male northern quolls were more active (male 1.27 g , s.d. = 0.41 female 1.18 g, s.d. = 0.36), spent more time walking (13.09% male: 8.93% female) and engaged in less lying/resting behaviour than female northern quolls (7.67% male: 23.65% female). Reduced resting behaviour among males could explain the post-breeding death as the deterioration in appearance reflects that reported for sleep-deprived rodents.

Balancing Biomechanical Constraints: Optimal Escape Speeds When There Is a Trade-off between Speed and Maneuverability

Publisher: Oxford University Press (OUP)

Date: 02-09-2015

DOI: 10.1093/ICB/ICV103

Abstract: The ability for prey to escape a pursuing predator is dependent both on the prey's speed away from the threat and on their ability to rapidly change directions, or maneuverability. Given that the biomechanical trade-off between speed and maneuverability limits the simultaneous maximization of both performance traits, animals should not select their fastest possible speeds when running away from a pursuing predator but rather a speed that maximizes the probability of successful escape. We explored how variation in the relationship between speed and maneuverability-or the shape of the trade-off-affects the optimal choice of speed for escaping predators. We used tablet-based games that simulated interactions between predators and prey (human subjects acting as predators attempting to capture "prey" moving across a screen). By defining a specific relationship between speed and maneuverability, we could test the survival of each of the possible behavioral choices available to this phenotype, i.e., the best combination of speed and maneuverability for prey fitness, based on their ability to escape. We found that the shape of the trade-off function affected the prey's optimal speed for success in escaping, the prey's maximum performance in escaping, and the breadth of speeds over which the prey's performance was high. The optimal speed for escape varied only when the trade-off between speed and maneuverability was non-linear. Phenotypes possessing trade-off functions for which maneuverability was only compromised at high speeds exhibited lower optimal speeds. Phenotypes that exhibited greater increases in maneuverability for any decrease in speed were more likely to have broader ranges of performance, meaning that in iduals could attain their maximum performance across a broader range of speeds. We also found that there was a differential response of the subject's learning to these different components of locomotion. With increased experience through repeated trials, subjects were able to successfully catch faster and faster dots. However, no improvement was observed in the subject's ability to capture more maneuverable prey. Our work highlights the costs of high-speed movement on other traits, including maneuverability, which make the use of an animal's fastest speeds unlikely, even when attempting to escape predators. By investigating the shape of the trade-off functions between speed and maneuverability and the way the environment and morphology mediates this trade-off, we can begin to understand why animals choose to move at the speeds they do when they are running away from predators or attempting to capture prey.

Smoothed Particle Hydrodynamics simulations of reef surf zone processes driven by plunging irregular waves

Publisher: Elsevier BV

Date: 03-2022

DOI: 10.1016/J.OCEMOD.2022.101945

Predicting the Movement Speeds of Animals in Natural Environments

Publisher: Oxford University Press (OUP)

Date: 22-10-2015

DOI: 10.1093/ICB/ICV106

Abstract: An animal's movement speed affects all behaviors and underlies the intensity of an activity, the time it takes to complete it, and the probability of successfully completing it, but which factors determine how fast or slow an animal chooses to move? Despite the critical importance of an animal's choice of speed (hereafter designated as "speed-choice"), we still lack a framework for understanding and predicting how fast animals should move in nature. In this article, we develop a framework for predicting speed that is applicable to any animal-including humans-performing any behavior where choice of speed occurs. To inspire new research in this area, we (1) detail the main factors likely to affect speed-choice, including organismal constraints (i.e., energetic, physiological, and biomechanical) and environmental constraints (i.e., predation intensity and abiotic factors) (2) discuss the value of optimal foraging theory in developing models of speed-choice and (3) describe how optimality models might be integrated with the range of potential organismal and environmental constraints to predict speed. We show that by utilizing optimality theory it is possible to provide quantitative predictions of optimal speeds across different ecological contexts. However, the usefulness of any predictive models is still entirely dependent on being able to provide relevant mathematical functions to insert into such models. We still lack basic knowledge about how an animal's speed affects its motor control, maneuverability, observational skills, and vulnerability to predators. Studies exploring these gaps in knowledge will help facilitate the field of optimal performance and allow us to adequately parameterize models predicting the speed-choice of animals, which represents one of the most basic of all behavioral decisions.

Molecular Hinges in Protein Folding:  the Urea-Denatured State of Apomyoglobin^†

Publisher: American Chemical Society (ACS)

Date: 25-09-2002

DOI: 10.1021/BI020381O

Abstract: Unfolded apomyoglobin in 8 M urea at pH 2.3 displays distinct regions with different backbone mobility, as monitored by NMR relaxation. These variations in backbone mobility can be correlated with intrinsic properties of the amino acids in the sequence. Clusters of small amino acids such as glycine and alanine show increased backbone mobility compared to the average. In contrast, local hydrophobic interactions that persist in urea denaturant cause some restriction of backbone motions on a picosecond to nanosecond time scale. The model derived from the behavior of apoMb in urea depends only on the most fundamental properties of the local amino acid sequence, and thus provides a feasible paradigm for the initiation of folding.

Solution Structure, Dynamics, and Hydrodynamics of the Calcium-bound Cross-reactive Birch Pollen Allergen Bet v 4 Reveal a Canonical Monomeric Two EF-Hand Assembly with a Regulatory Function

Publisher: Elsevier BV

Date: 03-2004

DOI: 10.1016/J.JMB.2003.12.070

Manganese accumulates in the brain of northern quolls (Dasyurus hallucatus) living near an active mine

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.ENVPOL.2017.10.088

Abstract: Mining is fundamental to the Australian economy, yet little is known about how potential contaminants bioaccumulate and affect wildlife living near active mining sites. Here, we show using air s ling that fine manganese dust within the respirable size range is found at levels exceeding international recommendations even 20 km from manganese extraction, processing, and storage facilities on Groote Eylandt, Northern Territory. Endangered northern quolls (Dasyurus hallucatus) living near mining sites were found to have elevated manganese concentrations within their hair, testes, and in two brain regions-the neocortex and cerebellum, which are responsible for sensory perception and motor function, respectively. Accumulation in these organs has been associated with adverse reproductive and neurological effects in other species and could affect the long-term population viability of northern quolls.

University Of Queensland

Location: Australia

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Universidade De Vigo Facultad De Ciencias

Location: Spain

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Universidade De Vigo

Location: Spain

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University Of Bayreuth

Location: Germany

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Discovery Projects - Grant ID: DP180103134

Start Date: 02-2018

End Date: 12-2021

Amount: $344,192.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150100198

Start Date: 2015

End Date: 12-2017

Amount: $355,100.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT150100492

Start Date: 06-2016

End Date: 06-2020

Amount: $928,552.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120101215

Start Date: 02-2012

End Date: 12-2015

Amount: $370,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0669687

Start Date: 2007

End Date: 12-2010

Amount: $270,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0344021

Start Date: 07-2003

End Date: 07-2006

Amount: $270,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160100736

Start Date: 12-2016

End Date: 12-2019

Amount: $325,000.00

Funder: Australian Research Council