Cluster PEACE observations of electron pressure tensor divergence in the magnetotail

Cluster crossed the magnetotail neutral sheet on four occasions between 16: 38 and 16: 43 UT on 08/17/2003. The four-spacecraft capabilities of Cluster are used to determine spatial gradients from the magnetic field vectors and, for the first time, full electron pressure tensors. We find that the contribution to the electric field from the Hall term (max of similar to 6 mV/m) pointed towards the neutral sheet, whereas that from the electron pressure divergence ( max of similar to 1 mV/m) pointed away from the neutral sheet. The electric field contributions in this direction were closely anti-correlated. During this period Clusters 1 and 4 were sometimes above and below the neutral sheet respectively. This allowed the simultaneous observation of magnetic fields that are interpreted as two quadrants of the Hall magnetic field system. An associated field-aligned current system was detected using the curlometer and moments of the particle distributions

Solving Potential Scattering Equations without Partial Wave Decomposition

Considering two-body integral equations we show how they can be dimensionally reduced by integrating exactly over the azimuthal angle of the intermediate momentum. Numerical solution of the resulting equation is feasible without employing a partial-wave expansion. We illustrate this procedure for the Bethe-Salpeter equation for pion-nucleon scattering and give explicit details for the one-nucleon-exchange term in the potential. Finally, we show how this method can be applied to pion photoproduction from the nucleon with $\pi N$ rescattering being treated so as to maintain unitarity to first order in the electromagnetic coupling. The procedure for removing the azimuthal angle dependence becomes increasingly complex as the spin of the particles involved increases.Comment: 15 pages, 4 figure

Fitness for purpose? project-based, collaborative learning in engineering undergraduate education

In response to evolving work practices in engineering (Royal Academy of Engineering 2010) and the ever-changing nature of vocational and professional knowledge (Broad, 2016), attention has rightly turned to the development of innovative pedagogies to facilitate the entry of graduates to the employment market. Project-based Learning (PjBL) is an example of such an innovative pedagogy and has been developed in some HE contexts to provide students with authentic learning experiences which are designed to embed team working and collaboration; problem solving and solution-finding alongside the development of technical knowledge and skills (Mills and Treagust, 2003). Yet despite the introduction of collaborative inquiry-based curricula in engineering, comprehensive understanding of the pedagogical practices that these innovative practices require has not yet emerged (Damşa & Nerland, 2016). At UCL Engineering, PjBL has been an integral feature of the Integrated Engineering Programme (IEP) undergraduate curriculum since 2014. Drawing upon an on-going collaborative Institute of Education/UCL ‘seed corn’ funded project, this paper will present data collected through observation of project-based learning scenarios and discussion with engineering undergraduates in situ. It will identify and discuss the nature of student learning and engagement in project-based learning activities, with particular attention to disciplinary issues and the development of student disciplinary knowledge. In so doing, it will assess whether PjBL is, indeed, ‘fit for purpose’

Chemical vapour deposition grown carbon nanotubes for interconnect technology

Multiwall carbon nanotubes have been grown by catalytic chemical vapour deposition using iron catalyst particles drop cast onto etched silicon wafers. The catalyst used was poly(styrene-vinylferrocene) in toluene solution which has an iron content of 2.1%. The etched silicon wafers have trench regions of varying widths ranging from 0.32 to 1 μm. For trench widths below 0.5 μm the number of “interconnecting” tubes growing from one side of the trench to the other increases sharply. A significant proportion of these “interconnects” are found to be Y-junction and multiple junction MWNTs. A systematic study of the effects of each of the growth conditions (temperature, run time, gas flow, catalyst concentration and trench width) versus interconnect yield was carried out. Densities of ~ 1.6 interconnects per micron of trench are obtained, with junction structures accounting for 38% of these interconnects. Densities can be controlled through modification of chemical vapour deposition conditions

Highlighting the learning in project-based undergraduate engineering education: pedagogical and methodological considerations

This paper presents a discussion of findings in relation to the pedagogy of Project Based Learning (PjBL) from a collaborative learning and teaching research project at UCL Engineering. It highlights the importance of adopting a) an understanding learning as a social practice in PjBL, and b) developing valid methodological approaches when capturing student learning experiences

Chimpanzee vocal communication: what we know from the wild

Vocal communication plays a vital role in the daily lives of our closest living relatives, chimpanzees. Unpacking the adaptive function of vocalisations, and the cognitive mechanisms underlying their production and comprehension is not only crucial for understanding chimpanzee behaviour, but also for inferring the capacities of our last common ancestors. Here, we review how observational and experimental methods have advanced our understanding of the vocal production and comprehension of wild chimpanzees. We discuss the impact of social and ecological factors on chimpanzee vocal communication, and review the inroads that have been made in elucidating the cognitive processes underpinning call production. We highlight approaches that may offer substantial future advances in knowledge and argue that whilst challenging to collect, data from wild populations is critical to building a comprehensive and accurate understanding of the communicative and cognitive abilities of our closest living relatives, and to tracing the evolutionary roots of human language

Detecting joint attention events in mother-infant dyads : sharing looks cannot be reliably identified by naïve third-party observers

Funding: This study was funded by an European Research Council Consolidator grant (ERC_CoG 2016_724608) awarded to KS (https://erc.europa.eu/funding/consolidator-grants).Joint attention, or sharing attention with another individual about an object or event, is a critical behaviour that emerges in pre-linguistic infants and predicts later language abilities. Given its importance, it is perhaps surprising that there is no consensus on how to measure joint attention in prelinguistic infants. A rigorous definition proposed by Siposova & Carpenter (2019) requires the infant and partner to gaze alternate between an object and each other (coordination of attention) and exchange communicative signals (explicit acknowledgement of jointly sharing attention). However, Hobson and Hobson (2007) proposed that the quality of gaze between individuals is, in itself, a sufficient communicative signal that demonstrates sharing of attention. They proposed that observers can reliably distinguish “sharing”, “checking”, and “orienting” looks, but the empirical basis for this claim is limited as their study focussed on two raters examining looks from 11-year-old children. Here, we analysed categorisations made by 32 naïve raters of 60 infant looks to their mothers, to examine whether they could be reliably distinguished according to Hobson and Hobson’s definitions. Raters had overall low agreement and only in 3 out of 26 cases did a significant majority of the raters agree with the judgement of the mother who had received the look. For the looks that raters did agree on at above chance levels, look duration and the overall communication rate of the mother were identified as cues that raters may have relied upon. In our experiment, naïve third party observers could not reliably determine the type of look infants gave to their mothers, which indicates that subjective judgements of types of look should not be used to identify mutual awareness of sharing attention in infants. Instead, we advocate the use of objective behaviour measurement to infer that interactants know they are ‘jointly’ attending to an object or event, and believe this will be a crucial step in understanding the ontogenetic and evolutionary origins of joint attention.Publisher PDFPeer reviewe

Degraded and computer-generated speech processing in a bonobo

The human auditory system is capable of processing human speech even in situations when it has been heavily degraded, such as during noise-vocoding, when frequency domain-based cues to phonetic content are strongly reduced. This has contributed to arguments that speech processing is highly specialized and likely a de novo evolved trait in humans. Previous comparative research has demonstrated that a language competent chimpanzee was also capable of recognizing degraded speech, and therefore that the mechanisms underlying speech processing may not be uniquely human. However, to form a robust reconstruction of the evolutionary origins of speech processing, additional data from other closely related ape species is needed. Specifically, such data can help disentangle whether these capabilities evolved independently in humans and chimpanzees, or if they were inherited from our last common ancestor. Here we provide evidence of processing of highly varied (degraded and computer-generated) speech in a language competent bonobo, Kanzi. We took advantage of Kanzi’s existing proficiency with touchscreens and his ability to report his understanding of human speech through interacting with arbitrary symbols called lexigrams. Specifically, we asked Kanzi to recognise both human (natural) and computer-generated forms of 40 highly familiar words that had been degraded (noise-vocoded and sinusoidal forms) using a match-to-sample paradigm. Results suggest that—apart from noise-vocoded computer-generated speech—Kanzi recognised both natural and computer-generated voices that had been degraded, at rates significantly above chance. Kanzi performed better with all forms of natural voice speech compared to computer-generated speech. This work provides additional support for the hypothesis that the processing apparatus necessary to deal with highly variable speech, including for the first time in nonhuman animals, computer-generated speech, may be at least as old as the last common ancestor we share with bonobos and chimpanzees

Declarative referential gesturing in a wild chimpanzee (Pan troglodytes)

Humans are argued to be unique in their ability and motivation to share attention with others about external entities—sharing attention for sharing’s sake. Indeed, in humans, using referential gestures declaratively to direct the attention of others toward external objects and events emerges in the first year of life. In contrast, wild great apes seldom use referential gestures, and when they do, it seems to be exclusively for imperative purposes. This apparent species difference has fueled the argument that the motivation and ability to share attention with others is a human-specific trait with important downstream consequences for the evolution of our complex cognition [M. Tomasello, Becoming Human (2019)]. Here, we report evidence of a wild ape showing a conspecific an item of interest. We provide video evidence of an adult female chimpanzee, Fiona, showing a leaf to her mother, Sutherland, in the context of leaf grooming in Kibale Forest, Uganda. We use a dataset of 84 similar leaf-grooming events to explore alternative explanations for the behavior, including food sharing and initiating dyadic grooming or playing. Our observations suggest that in highly specific social conditions, wild chimpanzees, like humans, may use referential showing gestures to direct others’ attention to objects simply for the sake of sharing. The difference between humans and our closest living relatives in this regard may be quantitative rather than qualitative, with ramifications for our understanding of the evolution of human social cognition