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.

The origin of diversity: studying the evolution of multi-faceted CD8+ T cell responses.

During the past two decades of research in T cell biology, an increasing number of distinct T cell subsets arising during the transition from naïve to antigen-experienced T cells have been identified. Recently, it has been appreciated that, in different experimental settings, distinct T cell subsets can be generated in parallel within the same immune response. While signals driving a single "lineage" path of T cell differentiation are becoming increasingly clear, it remains largely enigmatic how the phenotypic and functional diversification creating a multi-faceted T cell response is achieved. Here, we review current literature indicating that diversification is a stable trait of CD8(+) T cell responses. We showcase novel technologies providing deeper insights into the process of diversification among the descendants of individual T cells, and introduce two models that emphasize either intrinsic noise or extrinsic signals as driving forces behind the diversification of single cell-derived T cell progeny populations in vivo.

The Long-Term Effectiveness of Interventions Addressing Mental Health Literacy and Stigma of Mental Illness in Children and Adolescents: Systematic Review and Meta-Analysis.

Objectives: This study aims to provide a systematic review and meta-analysis of the literature on the long-term effects of interventions addressing children's and adolescents' mental health literacy and/or stigmatizing attitudes. Methods: Articles in English or German published between January 1997 and May 2020 were retrieved from five databases, leading to a total of 4,375 original articles identified. Results: 25 studies were included after applying exclusion criteria, 13 of which were eligible for meta-analysis. The overall average of the follow-up period was about 5 months. Long-term improvements were sustained for mental health literacy, d = 0.48, 95% CI = (0.34, 0.62), as well as for stigmatizing attitudes, d = 0.30, 95% CI = (0.24, 0.36), and social distance, d = 0.16, 95% CI = (0.03, 0.29). The combination of educational and contact components within interventions led to worse results for mental health literacy, but not stigmatizing attitudes or social distance. Conclusion: Interventions targeting children and adolescents generally have a brief follow-up period of an average of 5 months. They show a stable improvement in mental health literacy, but are to a lesser degree able to destigmatize mental illness or improve social distance.

The Normalization of Conservative Gender Politics in Chile and the Role of Civil Society.

The article discusses two cases of gender policy making during the Chilean transition to democracy, the policy on domestic violence and the divorce law. By comparing the official discourses on these two policy projects we show that authoritarian gender regimes can resist transition to democracy despite a vivid civil society. The case of Chile was selected, on one hand, because it exhibits particularly resistant authoritarian institutional enclaves. On the other hand, Chilean women's movements are often cited as a paragon of women's movements in transitions. Despite the central role of Chilean women's movements as a strong civil society force conservative gender roles and institutions inherited from the autocratic regime (e.g., conservative divorce and reproductive rights) have remained dominant. I argue that during the time of transition conservative political actors, but also parts of civil society, negotiated on these gender roles and institutions and thereby reached a status quo. Recent cases of sexual violence in response to student's uprisings show that this status quo is quite stable and prevents a real coming to terms with state violence.

Diving behavior in a free-living, semi-aquatic herbivore, the Eurasian beaver Castor fiber.

Semi-aquatic mammals have secondarily returned to the aquatic environment, although they spend a major part of their life operating in air. Moving both on land, as well as in, and under water is challenging because such species are considered to be imperfectly adapted to both environments. We deployed accelerometers combined with a depth sensor to study the diving behavior of 12 free-living Eurasian beavers Castor fiber in southeast Norway between 2009 and 2011 to examine the extent to which beavers conformed with mass-dependent dive capacities, expecting them to be poorer than wholly aquatic species. Dives were generally shallow (<1 m) and of short duration (<30 s), suggesting that the majority of dives were aerobic. Dive parameters such as maximum diving depth, dive duration, and bottom phase duration were related to the effort during different dive phases and the maximum depth reached. During the descent, mean vectorial dynamic body acceleration (VeDBA-a proxy for movement power) was highest near the surface, probably due to increased upthrust linked to fur- and lung-associated air. Inconsistently though, mean VeDBA underwater was highest during the ascent when this air would be expected to help drive the animals back to the surface. Higher movement costs during ascents may arise from transporting materials up, the air bubbling out of the fur, and/or the animals' exhaling during the bottom phase of the dive. In a manner similar to other homeotherms, beavers extended both dive and bottom phase durations with diving depth. Deeper dives tended to have a longer bottom phase, although its duration was shortened with increased VeDBA during the bottom phase. Water temperature did not affect diving behavior. Overall, the beavers' dive profile (depth, duration) was similar to other semi-aquatic freshwater divers. However, beavers dived for only 2.8% of their active time, presumably because they do not rely on diving for food acquisition.

A spherical-plot solution to linking acceleration metrics with animal performance, state, behaviour and lifestyle.

BACKGROUND: We are increasingly using recording devices with multiple sensors operating at high frequencies to produce large volumes of data which are problematic to interpret. A particularly challenging example comes from studies on animals and humans where researchers use animal-attached accelerometers on moving subjects to attempt to quantify behaviour, energy expenditure and condition. RESULTS: The approach taken effectively concatinated three complex lines of acceleration into one visualization that highlighted patterns that were otherwise not obvious. The summation of data points within sphere facets and presentation into histograms on the sphere surface effectively dealt with data occlusion. Further frequency binning of data within facets and representation of these bins as discs on spines radiating from the sphere allowed patterns in dynamic body accelerations (DBA) associated with different postures to become obvious. METHOD: We examine the extent to which novel, gravity-based spherical plots can produce revealing visualizations to incorporate the complexity of such multidimensional acceleration data using a suite of different acceleration-derived metrics with a view to highlighting patterns that are not obvious using current approaches. The basis for the visualisation involved three-dimensional plots of the smoothed acceleration values, which then occupied points on the surface of a sphere. This sphere was divided into facets and point density within each facet expressed as a histogram. Within each facet-dependent histogram, data were also grouped into frequency bins of any desirable parameters, most particularly dynamic body acceleration (DBA), which were then presented as discs on a central spine radiating from the facet. Greater radial distances from the sphere surface indicated greater DBA values while greater disc diameter indicated larger numbers of data points with that particular value. CONCLUSIONS: We indicate how this approach links behaviour and proxies for energetics and can inform our identification and understanding of movement-related processes, highlighting subtle differences in movement and its associated energetics. This approach has ramifications that should expand to areas as disparate as disease identification, lifestyle, sports practice and wild animal ecology. UCT Science Faculty Animal Ethics 2014/V10/PR (valid until 2017).

The Use of Acceleration to Code for Animal Behaviours; A Case Study in Free-Ranging Eurasian Beavers Castor fiber.

Recent technological innovations have led to the development of miniature, accelerometer-containing electronic loggers which can be attached to free-living animals. Accelerometers provide information on both body posture and dynamism which can be used as descriptors to define behaviour. We deployed tri-axial accelerometer loggers on 12 free-ranging Eurasian beavers Castor fiber in the county of Telemark, Norway, and on four captive beavers (two Eurasian beavers and two North American beavers C. canadensis) to corroborate acceleration signals with observed behaviours. By using random forests for classifying behavioural patterns of beavers from accelerometry data, we were able to distinguish seven behaviours; standing, walking, swimming, feeding, grooming, diving and sleeping. We show how to apply the use of acceleration to determine behaviour, and emphasise the ease with which this non-invasive method can be implemented. Furthermore, we discuss the strengths and weaknesses of this, and the implementation of accelerometry on animals, illustrating limitations, suggestions and solutions. Ultimately, this approach may also serve as a template facilitating studies on other animals with similar locomotor modes and deliver new insights into hitherto unknown aspects of behavioural ecology.

The smallest unit: effector and memory CD8(+) T cell differentiation on the single cell level.

CD8(+) T cell immune responses provide immediate protection against primary infection and durable memory capable of rapidly fighting off re-infection. Immediate protection and lasting memory are implemented by phenotypically and functionally distinct T cell subsets. While it is now widely accepted that these diverge from a common source of naïve T cells (T(n)), the developmental relation and succession of effector and memory T cell subsets is still under intense debate. Recently, a distinct memory T cell subset has been suggested to possess stem cell-like features, sparking the hope to harness its capacity for self-renewal and diversification for successful therapy of chronic infections or malignant diseases. In this review we highlight current developmental models of memory generation, T cell subset diversification and T cell stemness. We discuss the importance of single cell monitoring techniques for adequately mapping these developmental processes and take a brief look at signaling components active in the putative stem cell-like memory T cell compartment.

Disparate individual fates compose robust CD8+ T cell immunity.

A core feature of protective T cell responses to infection is the robust expansion and diversification of naïve antigen-specific T cell populations into short-lived effector and long-lived memory subsets. By means of in vivo fate mapping, we found a striking variability of immune responses derived from individual CD8(+) T cells and show that robust acute and recall immunity requires the initial recruitment of multiple precursors. Unbiased mathematical modeling identifies the random integration of multiple differentiation and division events as the driving force behind this variability. Within this probabilistic framework, cell fate is specified along a linear developmental path that progresses from slowly proliferating long-lived to rapidly expanding short-lived subsets. These data provide insights into how complex biological systems implement stochastic processes to guarantee robust outcomes.