Reinstatement of long-term memory following erasure of its behavioral and synaptic expression in Aplysia.

Long-term memory (LTM) is believed to be stored in the brain as changes in synaptic connections. Here, we show that LTM storage and synaptic change can be dissociated. Cocultures of Aplysia sensory and motor neurons were trained with spaced pulses of serotonin, which induces long-term facilitation. Serotonin (5HT) triggered growth of new presynaptic varicosities, a synaptic mechanism of long-term sensitization. Following 5HT training, two antimnemonic treatments-reconsolidation blockade and inhibition of PKM--caused the number of presynaptic varicosities to revert to the original, pretraining value. Surprisingly, the final synaptic structure was not achieved by targeted retraction of the 5HT-induced varicosities but, rather, by an apparently arbitrary retraction of both 5HT-induced and original synapses. In addition, we find evidence that the LTM for sensitization persists covertly after its apparent elimination by the same antimnemonic treatments that erase learning-related synaptic growth. These results challenge the idea that stable synapses store long-term memories

Characterization of LEO Satellites With All-Sky Photometric Signatures

We present novel techniques and methodology for unresolved photometric characterization of low-Earth Orbit (LEO) satellites. With the Pomenis LEO Satellite Photometric Survey our team has made over 14,000 observations of Starlink and OneWeb satellites to measure their apparent brightness. From the apparent brightness of each satellite, we calculate a new metric: the effective albedo, which quantifies the specularity of the reflecting satellite. Unlike stellar magnitude units, the effective albedo accounts for apparent range and phase angle and enables direct comparison of different satellites. Mapping the effective albedo from multiple observations across the sky produces an all-sky photometric signature which is distinct for each population of satellites, including the various sub-models of Starlink satellites. Space Situational Awareness (SSA) practitioners can use all-sky photometric signatures to differentiate populations of satellites, compare their reflection characteristics, identify unknown satellites, and find anomalous members. To test the efficacy of all-sky signatures for satellite identification, we applied a machine learning classifier algorithm which correctly identified the majority of satellites based solely on the effective albedo metric and with as few as one observation per individual satellite. Our new method of LEO satellite photometric characterization requires no prior knowledge of the satellite's properties and is readily scalable to large numbers of satellites such as those expected with developing communications mega-constellations.Comment: 11 pages, 8 figures, Proceedings of the 2022 AMOS Conferenc

P15. Employing students' multilingualism and language diversity in teaching and learning

Before our innovative clinical skills session ‘Interpreting in Consultations’, we conducted an annual survey of languages spoken by students on admission, in 2006, 2007 and 2008. Froma response rate of 94% we noted that 28% of students are advanced/fluent speakers of language(s) other than English and a total of 48 languages are spoken.The session, ‘Interpreting in Consultations’, involves first and second year students who speak the same language other than English, role-playing an ‘interpreted’ consultation.Feedback from tutors and students following the session shows that using different languages serves multiple, valuable purposes, highlighting:• issues encountered with interpreters• challenges of ‘medical’ language• difficulties in transmitting a patient centred approach• how linguistic and cultural sensitivities are lost in translation.Student linguistic diversity is considerable and not used to its full potential: the single clinical skills session we report suggests there is much more to be gained. The education we design and delivermay fail to recognise what patient-centred-ness means in different languages and cultures.Future research should: consider how to make best use of multiculturalism and linguistic diversity; explore how students’ awareness of, and competence in, different languages and culturescan be developed and maintained

Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of Gaia

The orbits of binary stars and planets, particularly eccentricities and inclinations, encode the angular momentum within these systems. Within stellar multiple systems, the magnitude and (mis)alignment of angular momentum vectors among stars, disks, and planets probes the complex dynamical processes guiding their formation and evolution. The accuracy of the \textit{Gaia} catalog can be exploited to enable comparison of binary orbits with known planet or disk inclinations without costly long-term astrometric campaigns. We show that \textit{Gaia} astrometry can place meaningful limits on orbital elements in cases with reliable astrometry, and discuss metrics for assessing the reliability of \textit{Gaia} DR2 solutions for orbit fitting. We demonstrate our method by determining orbital elements for three systems (DS Tuc AB, GK/GI Tau, and Kepler-25/KOI-1803) using \textit{Gaia} astrometry alone. We show that DS Tuc AB's orbit is nearly aligned with the orbit of DS Tuc Ab, GK/GI Tau's orbit might be misaligned with their respective protoplanetary disks, and the Kepler-25/KOI-1803 orbit is not aligned with either component's transiting planetary system. We also demonstrate cases where \textit{Gaia} astrometry alone fails to provide useful constraints on orbital elements. To enable broader application of this technique, we introduce the python tool \texttt{lofti\_gaiaDR2} to allow users to easily determine orbital element posteriors.Comment: 18 pages, 10 figures, accepted for publication in Ap

Should contributions to climate change be criminalised?

The climate is warming rapidly and the emissions-ceiling for ‘dangerous’ climate change approaches fast. The spectre of dreadful impacts to lives and ecosystems is materialising. Greenhouse gas sources must be made artificially scarce by state regulation and enforcement. Can criminalisation, the state’s strictest regulation, be justified for contributions to climate change? This thesis takes its lead from advocates of criminalising some contributions to climate change. It argues that existing discussion fails to address or satisfy conditions of morally permissible criminalisation set out in the normative criminalisation literature. But we won’t know whether we should criminalise contributions to climate change unless and until we’ve satisfied defensible theories of when criminalisation is morally justified. So, this thesis tackles normative questions head on. It contributes to the climate justice literature by considering criminal justice as a source of climate change mitigation. I test the strength of the moral case for criminalising contributions to climate change and offer systematically substantiated policy advice for climate justice theorists and activists alike. The thesis first identifies some candidate criminal offences, disambiguating what counts as a ‘contribution’ to climate change in the process. Then it evaluates two constraints on morally permissible criminalisation prevalent in the normative criminalisation literature: a harm constraint and a wrongness constraint. It rejects a harm constraint but adopts a wrongness constraint: the view that conduct criminalised must be morally wrong. It then demonstrates that criminalisation of contributions to climate change satisfies the wrongness constraint under certain conditions. But just because contributions to climate change can be criminalised doesn’t mean they should. The thesis finally investigates whether criminalisation would be proportionate to a) would-be offenders and b) society generally. It concludes that some, but not all, candidate offences would be proportionate in each respect

Evaluating wrongness constraints on criminalisation

Some claim that criminalisation is morally permissible only when the conduct criminalised is morally wrong. This claim can be disambiguated into at least three principles which differ according to whether, and how, wrongness is dependent on details of the law: the strong constraint, the moderate constraint, and the weak constraint. In this paper I argue that the weak wrongness constraint is preferable to the strong and moderate constraints. That is, we should prefer the view that conduct criminalised must be morally wrong, but qualifying wrongness can depend on criminalising the conduct first. Further, I will show that my arguments in support of the weak wrongness constraint have wider implications. Favouring the weak wrongness constraint implies that condemning wrongs cannot be the only legitimate reason in favour of criminalisation. Those who think condemnation can justify criminalisation should be pluralists

Habituation of the C-start response in larval zebrafish exhibits several distinct phases and sensitivity to NMDA receptor blockade.

The zebrafish larva has been a valuable model system for genetic and molecular studies of development. More recently, biologists have begun to exploit the surprisingly rich behavioral repertoire of zebrafish larvae to investigate behavior. One prominent behavior exhibited by zebrafish early in development is a rapid escape reflex (the C-start). This reflex is mediated by a relatively simple neural circuit, and is therefore an attractive model behavior for neurobiological investigations of simple forms of learning and memory. Here, we describe two forms of short-lived habituation of the C-start in response to brief pulses of auditory stimuli. A rapid form, persisting for ≥1 min but <15 min, was induced by 120 pulses delivered at 0.5-2.0 Hz. A more extended form (termed "short-term habituation" here), which persisted for ≥25 min but <1 h, was induced by spaced training. The spaced training consisted of 10 blocks of auditory pulses delivered at 1 Hz (5 min interblock interval, 900 pulses per block). We found that these two temporally distinguishable forms of habituation are mediated by different cellular mechanisms. The short-term form depends on activation of N-methyl-d-aspartate receptors (NMDARs), whereas the rapid form does not

Open source arc analyzer: Multi-sensor monitoring of wire arc additive manufacturing

Low-cost high-resolution metal 3-D printing remains elusive for the scientific community. Low-cost gas metal arc wire (GMAW)-based 3-D printing enables wire arc additive manufacturing (WAAM) for near net shape applications, but has limited resolution due to the complexities of the arcing process. To begin to monitor and thus control these complexities, the initial designs of the open source GMAW 3-D printer have evolved to include current and voltage monitoring. Building on this prior work, in this study, the design, fabrication and use of the open source arc analyzer is described. The arc analyzer is a multi-sensor monitoring system for quantifying the processing during WAAM, which includes voltage, current, sound, light intensity, radio frequency, and temperature data outputs. The open source arc analyzer is tested here on aluminum WAAM by varying wire feed rate and measuring the resultant changes in the sensor data. Visual inspection and microstructural analysis of the printed samples looking for the presence of porosity are used as the physical indicators of quality. The value of the sensors was assessed and the most impactful sensors were found to be the light and radio frequency sensors, which showed arc extinction events and a characteristic “good weld” peak frequency

The times are they a-changing? Evolving attitudes in Australian exercise science students’ attitudes towards sports concussion

The issue of concussion in sport continues to be discussed widely in the community as current and retired players reveal personal experiences, and concerns, about the long-term sequelae of their concussive injuries. This is the first study to examine evolving attitudes and beliefs towards concussion in sport by comparing data in an Australian exercise science student cohort between 2015 and 2020. Using a repeated cross-sectional design 1,013 participants (2020 cohort: n = 751; 21.6 ± 7.1 years; 2015 cohort: n = 312; 22.0 ± 5.2 years) responded to statements about concussion: personal attitudes; the media’s portrayal; elite athletes who continue to play concussed; if participants would continue to play on concussed; and on completing rehabilitation for concussion. Comparisons revealed statistically significant differences between cohorts across the majority of statements. Specifically, more progressive attitudes were found regarding the media presentation (glorification) of concussed athletes (decreased agreement of 14.7%, p < 0.001), admiration of concussed athletes who continued to play (decreased agreement of 10.5%, p < 0.001), and rehabilitation (increased agreement of 13%, p < 0.001). However, participants still presented attitudes of wishing to continue to train or play if they had a concussion for fear of letting team-mates down, or if the injury was not noticeable. While positive attitudes are evolving, more work is required, particularly as attitudes towards concussion still appear to be situation dependent