The Impact of Motor Learning on Motor Behavior and Cortical Dynamics in a Complex Stressful Social Environment

An economy of effort is a core characteristic of highly skilled motor performance often described as being effortless or automatic. Electroencephalographic (EEG) evaluation of cortical activity in elite performers has consistently revealed a reduction in extraneous associative cortical activity and an enhancement of task-relevant cortical processes. However, this has only been demonstrated under what are essentially practice-like conditions. Recently it has been shown that cerebral cortical activity becomes less efficient when performance occurs in a stressful, complex social environment. This dissertation examines the impact of motor skill training or practice on the EEG cortical dynamics that underlie performance in a stressful, complex social environment. Sixteen ROTC cadets participated in head-to-head pistol shooting competitions before and after completing nine sessions of skill training over three weeks. Spectral power increased in the theta frequency band and decreased in the low alpha frequency band after skill training. EEG Coherence increased in the left frontal region and decreased in the left temporal region after the practice intervention. These suggest a refinement of cerebral cortical dynamics with a reduction of task extraneous processing in the left frontal region and an enhancement of task related processing in the left temporal region consistent with the skill level reached by participants. Partitioning performance into ‘best’ and ‘worst’ based on shot score revealed that deliberate practice appears to optimize cerebral cortical activity of ‘best’ performances which are accompanied by a reduction in task-specific processes reflected by increased high-alpha power, while ‘worst’ performances are characterized by an inappropriate reduction in task-specific processing resulting in a loss of focus reflected by higher high-alpha power after training when compared to ‘best’ performances. Together, these studies demonstrate the power of experience afforded by practice, as a controllable factor, to promote resilience of cerebral cortical efficiency in complex environments.

THE INFLUENCE OF MOTIVATION ON EMOTION REGULATION AND MOTOR PERFORMANCE: EXAMINATION OF A NEURO-AFFECTIVE MODEL

Mental stress is known to disrupt the execution of motor performance and can lead to decrements in the quality of performance, however, individuals have shown significant differences regarding how fast and well they can perform a skilled task according to how well they can manage stress and emotion. The purpose of this study was to advance our understanding of how the brain modulates emotional reactivity under different motivational states to achieve differential performance in a target shooting task that requires precision visuomotor coordination. In order to study the interactions in emotion regulatory brain areas (i.e. the ventral striatum, amygdala, prefrontal cortex) and the autonomic nervous system, reward and punishment interventions were employed and the resulting behavioral and physiological responses contrasted to observe the changes in shooting performance (i.e. shooting accuracy and stability of aim) and neuro-cognitive processes (i.e. cognitive load and reserve) during the shooting task. Thirty-five participants, aged 18 to 38 years, from the Reserve Officers’ Training Corp (ROTC) at the University of Maryland were recruited to take 30 shots at a bullseye target in three different experimental conditions. In the reward condition, $1 was added to their total balance for every 10-point shot. In the punishment condition, $1 was deducted from their total balance if they did not hit the 10-point area. In the neutral condition, no money was added or deducted from their total balance. When in the reward condition, which was reportedly most enjoyable and least stressful of the conditions, heart rate variability was found to be positively related to shooting scores, inversely related to variability in shooting performance and positively related to alpha power (i.e. less activation) in the left temporal region. In the punishment (and most stressful) condition, an increase in sympathetic response (i.e. increased LF/HF ratio) was positively related to jerking movements as well as variability of placement (on the target) in the shots taken. This, coupled with error monitoring activity in the anterior cingulate cortex, suggests evaluation of self-efficacy might be driving arousal regulation, thus affecting shooting performance. Better performers showed variable, increasing high-alpha power in the temporal region during the aiming period towards taking the shot which could indicate an adaptive strategy of engagement. They also showed lower coherence during hit shots than missed shots which was coupled with reduced jerking movements and better precision and accuracy. Frontal asymmetry measures revealed possible influence of the prefrontal lobe in driving this effect in reward and neutral conditions. The possible interactions, reasons behind these findings and implications are discussed.

Credit risk & forward price models

Doutoramento em Gestão

O gigantesco passo da artilharia de campanha de 1914 para 1918

O presente trabalho de investigação tem como objetivo geral investigar os grandes progressos e inovações da Artilharia de Campanha no decorrer da Primeira Guerra Mundial. O período analisado está inserido no conflito da Primeira Guerra Mundial de 1914-1918, que se caracterizou fundamentalmente por ser um conflito onde existiu pouca mobilidade, uma quantidade excessiva de mortes e um desenvolvimento progressivo de armamento pesado para fazer face ao impasse provocado por uma guerra essencialmente de trincheiras. O crescimento exponencial da artilharia tornou-se, então, uma urgente necessidade num conflito onde a inovação dos materiais se sobrepôs à quantidade de homens. Para a elaboração deste trabalho de investigação aplicada, tendo como modelo o método da investigação histórica, foi analisada, numa abordagem diacrónica, o desenvolvimento da materiais e doutrinas utilizados pelas unidades de artilharia, sendo destacados essencialmente os exércitos da Alemanha, França e Grã-Bretanha. Por outro lado, numa abordagem sincrónica, foram identificadas as distintas inovações tais como o nascimento de novos tipos de artilharia, grande diversificação nas munições, tendência para a artilharia de tiro indireto substituir a de tiro direto, desenvolvimentos no controlo do tiro, novas formas de comunicação, artilharia de muito maior alcance, entre outros, pelo que este trabalho tem como finalidade demonstrar o papel da artilharia na criação do sistema de trincheiras e posteriormente no ultrapassar da imobilidade destas. Este trabalho baseia-se na análise de conteúdo de fontes primárias manuscritas e impressas, textuais e iconográficas, nacionais e internacionais, diretamente relacionadas com o tema abordado.

Technical performance profile of the four-time Costa Rican senior basketball league championship team

The purpose of this study was to analyze and compare the technical performance profile of the four-time Costa Rican Senior Basketball League championship team. A total of 142 games was recorded throughout the 2007, 2008 and 2009 seasons. Performance indicators selected were: two and three-point shots (converted, missed, effectiveness rates), free throws (converted, missed, effectiveness rates), points, offensive and defensive rebounds, fouls, turnovers, assists and ball steals. The information was described based on absolute and relative frequency values. Data was compared by season and by playing period based on the following non-parametric techniques: U-test, Friedman test and Chi-square. In all cases, SPSS version 15.0 was used with a significance level of p ≤ 0.05. Results showed a better profile of technical performance in the 2008 season, characterized by better percentages of two-point shots, free throws, fewer turnovers and more ball steals and assists. In relation to the playing period, the team showed a better technical performance profile during the second half of the matches. In general, the effectiveness rate of two-point shots and free throws was above 60% in both playing periods, while the three-point shot percentage ranged between 26.4% and 29.2%. In conclusion, the team showed a similar technical performance profile to that reported in the literature, as well as a clear evidence of the importance of recording and following up on technical performance indicators in basketball.

Time-motion analysis of test and one-day international cricket centuries

The aim of this study was to quantify movement patterns of batsmen scoring 100 runs (century), including analysis at 50, 80, and 100 runs, in Test and One-Day international (one-day) matches and between the first and second 50 within a Test century. Test centuries (n = 13) and one-day scores above 80 (n = 12) filmed during the 2005 - 2006 Australian international season were analysed for movement patterns of standing, walking, jogging, striding, sprinting, shot playing, and turning. At each run target, differences in total time, duration of individual movement pattern, movement pattern frequency, and number of balls faced were determined between Test and one-day matches (analysis of variance). Differences within Test centuries were assessed using paired t-tests. A similar fractional predominance of time spent in low-intensity activity (standing and walking) between Test and one-day matches at each run target (94 and 96% respectively) was observed, with no differences in duration of striding or sprinting (Test: 1.1 min, s = 0.5; one-day: 0.9 min, s = 0.5 for sprinting: P = 0.28). A 37% longer total duration occurred in Tests, resulting in longer recovery bouts between high-intensity efforts. There were no differences between the first and second 50 runs of a Test century for any measure (P at best = 0.34). In summary, Test and one-day centuries are characterized by much low-intensity activity and patterns of high-intensity activity similar to many repeat-sprint team sports and greater recovery breaks in longer matches.

Duplicity of meaning

This article considers the ‘duplicitous’ functions of the word ‘wild’ in the arguments over the Queensland’s Wild Rivers Act 2005. Certain traditional owners, environmentalist and state groups have deployed the term pragmatically, simultaneously endorsing its usage (through repetition) and disavowing its colonial associations (through explanation) against protestations by Indigenous and non-Indigenous stakeholders. In a sense, this ambivalent ‘duplicity’ is entirely consistent with relations between the settler-colonial nation state and Aboriginal and Torres Strait Islander polities – relations aptly characterised by Povinelli as shaped by ‘the cunning of recognition’ – which stratify relations between groups through the endorsing of ‘tradition’. Thus ‘the Indigenous’ can be posited both as one political minority amidst a multicultural polity and as a pre-modern and endemic precursor of the settler-colonial nation, constitutively conservationist ‘first Australians’. Arguably, in the legislation’s ‘recognition’ of the ‘wild’ past, Indigenous peoples – who were known in nineteenth century Queensland as ‘wild blacks’ or ‘myalls’ (meaning those who resisted leaving their lands – and ‘could be shot with impunity’) are recouped as the nation’s first caretakers of ‘pristine’ waterways. However, this article regards the current use of this ambivalent word as also potentially authorising those recognised through this mythic form, providing a limited and uncertain opportunity for traditional owners to ground a form of sovereign right in lands and waterways. Against totalising settler-colonial critiques of hegemony, this article argues that the Wild Rivers legislation does not forget indigeneity, but rather relies on indigeneity. While much research concerning ‘natural’ ideologies such as ‘the noble savage’ has worked to show that faith in a belated era of historical fullness or presence can serve to evacuate the present of material details, it may also be that the ‘wild’ can also offer Indigenous peoples a valuable political authority to, in the words of Courtney Jung, ‘contest the exclusions through which it has been constituted’.

Documentary Intersect

I started by collecting things in order to inform my work. What seems to have happened slowly is that the collections eventually became my work. – Patrick Pound The New Zealand-born, Melbourne-based artist Patrick Pound has had a long-term engagement with the work of Walker Evans, both as a writer and as a practicing artist. For his solo exhibition at the Adam Art Gallery, Pound developed an installation comprised of found images, taking his cue from Walker Evans’s practice of working with readymade printed matter which he published in magazines such as Fortune and Architectural Forum. While Pound’s collecting habits are voracious, he is also a great organiser. He is interested in typologies and arranges items according to shared content: ‘tears’, ‘floral clocks’, ‘crime scenes’, ‘sleepers’, and so on. Laying these out in linear sequences Pound discovers points of intersection to create complex grids of structured yet chaotic imagery. A Hollywood film still of a crime scene will sit eerily alongside an image of a real deceased subject sourced from an archive; or a set of postcards will show the same subject, shot by different photographers and describing both changing viewpoints and the passage of time. Pound has stated: ‘People make sense of the world through assembling, listing and categorising…meaning is to be found in the accumulation of [these] details.’

Somewhere else

Faraways, 2012, 10 minMagic Miles, 2014, 15 minTelescope, 2013, 80 minAudrey Lam's films follow people in situations and places familiar to her, them and others they know. Sometimes moments and landscapes are revisited in some way to remember thoughts and time missed.Telescope is a time-lapse of reflections, changes in sunlight of Dirk de Bruyn’s backyard, assembled over 20 years. Telescope starts in Super 8 and ends with digital video, shot mostly while his family were themselves at work, somewhere else. It is an emptied landscape.Audrey Lam was born in Hong Kong and lives in Australia. She studied film and photography at Queensland College of Art. She has participated in art festivals including Next Wave, Otherfilm and Yebisu, and her films have screened at film festivals in London, Rotterdam and Oberhausen. Her work often builds on shared experiences, re-chronicling everyday encounters to reflect on the nuances of place and belonging. She has been developing new work during her Asialink arts residency at Green Papaya Art Projects.Dirk de Bruyn was born in the Netherlands and migrated with his family to Australia in 1958 as young child. He has made numerous experimental, documentary and animation films, videos and performance and installation work over the last 40 years. He was a founding member and past president of MIMA (Experimenta). His book The Performance of Trauma in Moving Image Art was published in 2014.

La cinématographie-attraction à Montréal à la lumière de la législation (1896-1913)

La cinématographie-attraction a longtemps été considérée comme les débuts du cinéma, jusqu’à ce qu’une controverse, en 1978, marque une rupture historiographique et la considère comme un objet d’études à part entière, distinct du cinéma institutionnel. Nous l’analysons ici dans le contexte de Montréal, entre la présentation du Cinématographe Lumière en 1896 et l’entrée en fonction du Bureau de censure des vues animées de la province du Québec en 1913. Plus précisément, nous interrogeons son institutionnalisation à la lumière de la législation ; les représentants du gouvernement canadien donnent un statut juridique aux vues animées en modifiant et en votant des textes légaux. Cette étude définit le contexte cinématographique, historique et géographique. Elle aborde ensuite trois domaines de la cinématographie-attraction qui ne sont pas les mêmes que ceux du cinéma : la fabrication (le financement, le tournage et la modification des œuvres cinématographiques), l’exhibition (les séances de projections payantes d’images animées) et la réception (les jugements portés sur les vues animées). Nous montrons comment la cinématographie-attraction est d’abord contrôlée par de nombreuses personnes (celles qui financent, celles qui tournent les vues animées, les propriétaires de lieux d’amusements, le policier ou le pompier présent au cours des projections), puis par des institutions reconnues et les représentants du gouvernement. En nous appuyant sur la presse montréalaise, les discours officiels, les discours diocésains, les textes légaux, les catalogues publiés par les compagnies de fabrication et sur les vues animées, nous montrons quels sont les enjeux de l’institutionnalisation pour les différents groupes sociaux.

Confronto tra le tecniche XRD e IHD per la misura di tensioni residue

Le rotture a fatica dei componenti sono dovute principalmente alle tensioni di trazione generate da carichi ciclici e variabili nel tempo. Le cricche causate da questo tipo di tensioni possono propagarsi e crescere fino a causare danni catastrofici nel componente. La fatica costituisce uno dei fattori principali di rottura delle strutture aeronautiche; in campo aeronautico sono quindi molto diffusi dei trattamenti superficiali che permettono di indurre tensioni di compressione che contrastano quelle di trazione, in modo tale da ritardare o prevenire le rotture dovute al fenomeno della fatica. Esistono diverse tecniche per raggiungere questo risultato e permettere di prolungare la vita a fatica di un componente metallico, la più nota è sicuramente il Laser Shock Peening (LSP). Nel corso degli ultimi anni la maggior parte delle ricerche condotte rispetto a questa tecnica sono state incentrate sugli effetti meccanici che questo trattamento ha sul materiale in modo da determinare la configurazione ottimale per ottenere una distribuzione delle tensioni il più efficace possibile ai fini della vita a fatica; sono state svolte diverse prove sperimentali per studiare il ruolo dei parametri del laser e ottimizzare la procedura del LSP. Tra le tecniche utilizzate per valutare gli effetti del LSP in termini di tensioni residue, spiccano, oltre ai metodi computazionali, l'X-ray Diffraction (XRD) e l'Incremental Hole Drilling (IHD). L'elaborato di tesi qui presentato ha come scopo il confronto tra i livelli di tensioni residue riscontrate all'interno di provini sottili in lega di alluminio, sottoposti a differenti trattamenti laser, attraverso i suddetti metodi XRD e IHD. I risultati, già noti, ottenuti con la tecnica l'XRD sono stati posti a verifica attraverso dei test svolti con l'IHD presso i laboratori MaSTeRLab della Scuola di Ingegneria dell'Università di Bologna.

Unity in Christ or Pan-Europeanism?:Nathan Söderblom and the ecumenical peace movement in the interwar period

In the summer of 2014 the Swedish Church is celebrating the 100th anniversary of the appointment of Nathan Söderblom as archbishop of Uppsala, and thus head of the Swedish church organisation. As a Lutheran with an enormously broad-minded and broad-reaching approach to ecumenical understanding and community-building, Söderblom shot to prominence in the interwar period not only because of his ecumenical engagement, calling for an evangelical catholicity so stand side by side with the Roman catholic and Orthodox catholic traditions, but also because of his comprehensive secular engagement for peace and understanding between peoples. In the latter context he also acquired a solid reputation as a perhaps less prominent but still noteworthy figure in the history of European integration. This article investigates how, why and to what extent Söderblom’s ecumenical and secular engagements were intertwined. The first part discusses how his biographical and academic background led to such staunch ecumenical positions, while the second part focuses on the secular engagement, which was perceived by Söderblom as necessary to make progress on the ecumenical front in the practical political realities of the 1920s. The final part, comparing and contrasting Söderblom’s views with those of Count Richard von Coudenhove-Calergi and the Pan-European Union, demonstrates why Söderblom’s engagement for Europe had to be limited: unity in Christ is by definition global in nature and therefore cannot be continent-specific.

La cinématographie-attraction à Montréal à la lumière de la législation (1896-1913)

La cinématographie-attraction a longtemps été considérée comme les débuts du cinéma, jusqu’à ce qu’une controverse, en 1978, marque une rupture historiographique et la considère comme un objet d’études à part entière, distinct du cinéma institutionnel. Nous l’analysons ici dans le contexte de Montréal, entre la présentation du Cinématographe Lumière en 1896 et l’entrée en fonction du Bureau de censure des vues animées de la province du Québec en 1913. Plus précisément, nous interrogeons son institutionnalisation à la lumière de la législation ; les représentants du gouvernement canadien donnent un statut juridique aux vues animées en modifiant et en votant des textes légaux. Cette étude définit le contexte cinématographique, historique et géographique. Elle aborde ensuite trois domaines de la cinématographie-attraction qui ne sont pas les mêmes que ceux du cinéma : la fabrication (le financement, le tournage et la modification des œuvres cinématographiques), l’exhibition (les séances de projections payantes d’images animées) et la réception (les jugements portés sur les vues animées). Nous montrons comment la cinématographie-attraction est d’abord contrôlée par de nombreuses personnes (celles qui financent, celles qui tournent les vues animées, les propriétaires de lieux d’amusements, le policier ou le pompier présent au cours des projections), puis par des institutions reconnues et les représentants du gouvernement. En nous appuyant sur la presse montréalaise, les discours officiels, les discours diocésains, les textes légaux, les catalogues publiés par les compagnies de fabrication et sur les vues animées, nous montrons quels sont les enjeux de l’institutionnalisation pour les différents groupes sociaux.

Summer reading series #2 : seeing eye to eye

Martin Rumsby’s Eye I Aye (2007) appears a straightforward, almost naive film. A camera is zoomed into a flat image of a community bench in front of a shop, with cars and some pedestrians passing by. It could be any suburban street. At times the de-facto main characters Dida and Erana or their surrogates are seated there, both are of mixed race from Māori and Pākehā parents and the soundtrack frames their ‘history’. This meditation is interrupted by the weather, with sheets of raindrops caught by the camera’s autofocus, patterning the window, wiping out the outside scene. Later Rumsby also inserts his body and face between the camera and window, his eyes in shot re-securing the camera’s position. This technical tampering registers as unsettling and suspicious.

Tenerbrosity scene 1

Tenerbrosity Scene 1, is a large format photographic artwork. The work visually explores memory through the recollection of incidents and the fragility of truth. This is situated within the practice of landscape photography in a post-colonial framework. In Scene 1 of 2, a woodland closed shot is presented for the audience. The scene was shot at night in a forest, and provides a focus on the details of trees and leaves, branches and an emerging blackness that surrounds the scene. The journey has taken a strange turn in Tenerbrosity, with suggestions of the strange and unfamiliar, like a fragment or a moment, attempting to pull everything back together, somehow..somewhere… The size of the work as a large unframed print on canvas, actively seeks a physical engagement with the audience via a centrality of vision. The artwork hangs a metre out from the wall and the work sways in the breeze, to ensure the audience is located at a site for the production of meaning and this captures a mixed reality, between artwork, vision, audience and experience. This is achieved to engage with the multi-sequential narratives surrounding traces of memories and decay visually and theoretically traversed throughout the series. This is part of the ongoing exploration of states of the in-between and forms the 1st in a series of 2 artworks. The work is exhibited in the Yarra Ranges, because the work explores the narratives of the decay of memory experienced in this location. Exhibiting here allows a cyclic dialogue with notions of place, home, longing and loss.