Can acquisition of expertise be supported by technology?

Professional trainees in the workplace are increasingly required to demonstrate specific standards of competence. Yet, empirical evidence of how professionals acquire competence in practice is lacking. The danger, then, is that efforts to support learning processes may be misguided. We hypothesised that a systemic view of how expertise is acquired would support more timely and appropriate development of technology to support workplace learning. The aims of this study were to provide an empirically based understanding of workplace learning and explore how learning could be facilitated through suitable application of technology. We have used the medical specialist trainee as an exemplar of how professionals acquire expertise within a complex working environment. We describe our methodological approach, based on the amalgam of systems analysis and qualitative research methods. We present the development of a framework for analysis and early findings from qualitative data analysis. Based on our findings so far, we present a tentative schema representing how technology can support learning with suggestions for the types of technology that could be used

Influence of Sonication Parameters on the Morphology of Nanocellulose Aerogels

Nanocellulose is a renewable and biocompatible material that has a tensile strength similar to aluminum, is stiffer than Kevlar, and has a strength to weight ratio eight times that of stainless steel. There has been a range of studies on nanocellulose materials for potential use as a low-calorie food substitute, biomedical wound dressings, and as a structural component for buildings. Throughout this research experiment, nanocellulose aerogels of different mass compositions were created through a mechanical process using an ultrasonic processor with a titanium probe attachment. The purpose of this study was to develop a method that reduces the amount titanium contamination in the nanocellulose aerogels by influencing the sonication parameters. As a result, the ultrasonication processing time of nanocellulose aerogels was drastically reduced consequently reducing potential contamination from the titanium probe

A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with Arbitrary Quadrupole Moments. I. Quasi-Kerr Black Holes

We describe a new numerical algorithm for ray tracing in the external spacetimes of spinning compact objects characterized by arbitrary quadrupole moments. Such spacetimes describe non-Kerr vacuum solutions that can be used to test the no-hair theorem in conjunction with observations of accreting black holes. They are also appropriate for neutron stars with spin frequencies in the 300-600 Hz range, which are typical of the bursting sources in low-mass X-ray binaries. We use our algorithm to show that allowing for the quadrupole moment of the spacetime to take arbitrary values leads to observable effects in the profiles of relativistic broadened fluorescent iron lines from geometrically thin accretion disks.Comment: submitted to the Astrophysical Journa

Testing the No-Hair Theorem with Observations in the Electromagnetic Spectrum: II. Black-Hole Images

According to the no-hair theorem, all astrophysical black holes are fully described by their masses and spins. This theorem can be tested observationally by measuring (at least) three different multipole moments of the spacetimes of black holes. In this paper, we analyze images of black holes within a framework that allows us to calculate observables in the electromagnetic spectrum as a function of the mass, spin, and, independently, the quadrupole moment of a black hole. We show that a deviation of the quadrupole moment from the expected Kerr value leads to images of black holes that are either prolate or oblate depending on the sign and magnitude of the deviation. In addition, there is a ring-like structure around the black-hole shadow with a diameter of about 10 black-hole masses that is substantially brighter than the image of the underlying accretion flow and that is independent of the astrophysical details of accretion flow models. We show that the shape of this ring depends directly on the mass, spin, and quadrupole moment of the black hole and can be used for an independent measurement of all three parameters. In particular, we demonstrate that this ring is highly circular for a Kerr black hole with a spin a<0.9M, independent of the observer's inclination, but becomes elliptical and asymmetric if the no-hair theorem is violated. Near-future very-long baseline interferometric observations of Sgr A* will image this ring and may allow for an observational test of the no-hair theorem.Comment: Accepted for publication in Ap

Decision Making in Mice During an Optimized Touchscreen Spatial Working Memory Task Sensitive to Medial Prefrontal Cortex Inactivation and NMDA Receptor Hypofunction

Working memory is a fundamental cognitive process for decision-making and is a hallmark impairment in a variety of neuropsychiatric and neurodegenerative diseases. Spatial working memory paradigms are a valuable tool to assess these processes in rodents and dissect the neurobiology underlying working memory. The trial unique non-match to location (TUNL) task is an automated touchscreen paradigm used to study spatial working memory and pattern separation processes in rodents. Here, animals must remember the spatial location of a stimulus presented on the screen over a delay period; and use this representation to respond to the novel location when the two are presented together. Because stimuli can be presented in a variety of spatial configurations, TUNL offers a trial-unique paradigm, which can aid in combating the development of unwanted mediating strategies. Here, we have optimized the TUNL protocol for mice to reduce training time and further reduce the potential development of mediating strategies. As a result, mice are able to accurately perform an enhanced trial-unique paradigm, where the locations of the sample and choice stimuli can be presented in any configuration on the screen during a single session. We also aimed to pharmacologically characterize this updated protocol, by assessing the roles of the medial prefrontal cortex (mPFC) and N-methyl-D-aspartate (NMDA) receptor (NMDAr) functioning during TUNL. Temporary inactivation of the medial prefrontal cortex (mPFC) was accomplished by directly infusing a mixture of GABA agonists muscimol and baclofen into the mPFC. We found that mPFC inactivation significantly impaired TUNL performance in a delay-dependent manner. In addition, mPFC inactivation significantly increased the susceptibility of mice to proactive interference. Mice were then challenged with acute systemic injections of the NMDAr antagonist ketamine, which resulted in a dose-dependent, delay-dependent working memory impairment. Together, we describe an optimized automated touchscreen task of working memory, which is dependent on the intact functioning of the mPFC and sensitive to acute NMDAr hypofunction. With the vast genetic toolbox available for modeling disease and probing neural circuit functioning in mice, the TUNL task offers a valuable paradigm to pair with these technologies to further investigate the processes underlying spatial working memory

Mouse Performance on a Novel Touchscreen Continuous Performance Task is Dependent on Signaling in the Prelimbic Cortex

Attention is the cognitive processing that facilitates the ability to target and attend to relevant environmental stimuli, while filtering out irrelevant or distracting stimuli. Control over selective attention is theorized to be dependent on organized neural communication that stems from the medial prefrontal cortex (mPFC). To evaluate selective and sustained attention, mice were trained on the novel touchscreen rodent continuous performance task (rCPT), a task designed to emulate the human CPT. In the rodent version, images are continuously presented on a touchscreen, where mice have been trained to selectively respond to one image type while suppressing responses to all others. Following training on the rCPT, bilateral cannulas were implanted into the prelimbic region of the mPFC. Immediately prior to cognitive testing, a mixture of GABA A and B agonists were infused into the prelimbic to temporarily inactivate the structure. Inactivating the prelimbic cortex significantly impaired performance on this task, resulting in a reduced ability to discriminate the target from non-target images, as well as a reduction in speed and overall responding. Currently, mice expressing optogenetic receptors are being used to evaluate how parvalbumin interneuron activity within the prelimbic cortex influences attentional performance on the rCPT. As the parvalbumin interneuron population is heavily implicated in generating coordinated neuronal activity and supporting cognition, it is predicted that inhibiting these interneurons and altering synchronous prelimbic activity will impair rCPT performance

Habitat configurations shape the trophic and energetic dynamics of reef fishes in a tropical–temperate transition zone: implications under a warming future

Understanding the extent to which species’ traits mediate patterns of community assembly is key to predict the effect of natural and anthropogenic disturbances on ecosystem functioning. Here, we apply a trait-based community assembly framework to understand how four different habitat configurations (kelp forests, Sargassum spp. beds, hard corals, and turfs) shape the trophic and energetic dynamics of reef fish assemblages in a tropical–temperate transition zone. Specifically, we tested (i) the degree of trait divergence and convergence in each habitat, (ii) which traits explained variation in species’ abundances, and (iii) differences in standing biomass (kg ha−1), secondary productivity (kg ha−1 day−1) and turnover (% day−1). Fish assemblages in coral and kelp habitats displayed greater evidence of trait convergence, while turf and Sargassum spp. habitats displayed a higher degree of trait divergence, a pattern that was mostly driven by traits related to resource use and thermal affinity. This filtering effect had an imprint on the trophic and energetic dynamics of reef fishes, with turf habitats supporting higher fish biomass and productivity. However, these gains were strongly dependent on trophic guild, with herbivores/detritivores disproportionately contributing to among-habitat differences. Despite these perceived overall gains, turnover was decoupled for fishes that act as conduit of energy to higher trophic levels (i.e. microinvertivores), with coral habitats displaying higher rates of fish biomass replenishment than turf despite their lower productivity. This has important implications for biodiversity conservation and fisheries management, questioning the long-term sustainability of ecological processes and fisheries yields in increasingly altered marine habitats.publishedVersio

Habitat configurations shape the trophic and energetic dynamics of reef fishes in a tropical–temperate transition zone:implications under a warming future

Understanding the extent to which species’ traits mediate patterns of community assembly is key to predict the effect of natural and anthropogenic disturbances on ecosystem functioning. Here, we apply a trait-based community assembly framework to understand how four different habitat configurations (kelp forests, Sargassum spp. beds, hard corals, and turfs) shape the trophic and energetic dynamics of reef fish assemblages in a tropical–temperate transition zone. Specifically, we tested (i) the degree of trait divergence and convergence in each habitat, (ii) which traits explained variation in species’ abundances, and (iii) differences in standing biomass (kg ha(−1)), secondary productivity (kg ha(−1) day(−1)) and turnover (% day(−1)). Fish assemblages in coral and kelp habitats displayed greater evidence of trait convergence, while turf and Sargassum spp. habitats displayed a higher degree of trait divergence, a pattern that was mostly driven by traits related to resource use and thermal affinity. This filtering effect had an imprint on the trophic and energetic dynamics of reef fishes, with turf habitats supporting higher fish biomass and productivity. However, these gains were strongly dependent on trophic guild, with herbivores/detritivores disproportionately contributing to among-habitat differences. Despite these perceived overall gains, turnover was decoupled for fishes that act as conduit of energy to higher trophic levels (i.e. microinvertivores), with coral habitats displaying higher rates of fish biomass replenishment than turf despite their lower productivity. This has important implications for biodiversity conservation and fisheries management, questioning the long-term sustainability of ecological processes and fisheries yields in increasingly altered marine habitats. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00442-022-05278-6

Masses of Nearby Supermassive Black Holes with Very-Long Baseline Interferometry

Dynamical mass measurements to date have allowed determinations of the mass M and the distance D of a number of nearby supermassive black holes. In the case of Sgr A*, these measurements are limited by a strong correlation between the mass and distance scaling roughly as M ~ D^2. Future very-long baseline interferometric (VLBI) observations will image a bright and narrow ring surrounding the shadow of a supermassive black hole, if its accretion flow is optically thin. In this paper, we explore the prospects of reducing the correlation between mass and distance with the combination of dynamical measurements and VLBI imaging of the ring of Sgr A*. We estimate the signal to noise ratio of near-future VLBI arrays that consist of five to six stations, and we simulate measurements of the mass and distance of Sgr A* using the expected size of the ring image and existing stellar ephemerides. We demonstrate that, in this best-case scenario, VLBI observations at 1 mm can improve the error on the mass by a factor of about two compared to the results from the monitoring of stellar orbits alone. We identify the additional sources of uncertainty that such imaging observations have to take into account. In addition, we calculate the angular diameters of the bright rings of other nearby supermassive black holes and identify the optimal targets besides Sgr A* that could be imaged by a ground-based VLBI array or future space-VLBI missions allowing for refined mass measurements.Comment: 8 pages, 4 figures, 2 tables, refereed version, accepted for publication in Ap

The renaissance of Odum\u27s outwelling hypothesis in \u27blue carbon\u27 science

The term ‘Blue Carbon’ was coined about a decade ago to highlight the important carbon sequestration capacity of coastal vegetated ecosystems. The term has paved the way for the development of programs and policies that preserve and restore these threatened coastal ecosystems for climate change mitigation. Blue carbon research has focused on quantifying carbon stocks and burial rates in sediments or accumulating as biomass. This focus on habitat-bound carbon led us to losing sight of the mobile blue carbon fraction. Oceans, the largest active reservoir of carbon, have become somewhat of a blind spot. Multiple recent investigations have revealed high outwelling (i.e., lateral fluxes or horizontal exports) of dissolved inorganic (DIC) and organic (DOC) carbon, as well as particulate organic carbon (POC) from blue carbon habitats. In this paper, we conceptualize outwelling in mangrove, saltmarsh, seagrass and macroalgae ecosystems, diagnose key challenges preventing robust quantification, and pave the way for future work integrating mobile carbon in the blue carbon framework. Outwelling in mangroves and saltmarshes is usually dominated by DIC (mostly as bicarbonate), while POC seems to be the major carbon species exported from seagrass meadows and macroalgae forests. Carbon outwelling science is still in its infancy, and estimates remain limited spatially and temporally. Nevertheless, the existing datasets imply that carbon outwelling followed by ocean storage is relevant and may exceed local sediment burial as a long-term ( \u3e centuries) blue carbon sequestration mechanism. If this proves correct as more data emerge, ignoring carbon outwelling may underestimate the perceived sequestration capacity of blue carbon ecosystems