Competition between disorder and exchange splitting in superconducting ZrZn2

We propose a simple picture for the occurrence of superconductivity and the pressure dependence of the superconducting critical temperature, T-SC, in ZrZn2. According to our hypothesis the pairing potential is independent of pressure, but the exchange splitting, E-xc leads to a pressure dependence in the (spin dependent) density of states at the Fermi level, D-sigma (epsilon(F)). Assuming p-wave pairing T-SC is dependent on D-sigma (epsilonF) which ensures that, in the absence of non-magnetic impurities, T-SC decreases as pressure is applied until it reaches a minimum in the paramagnetic state. Disorder reduces this minimum to zero, this gives the illusion that the superconductivity disappears at the same pressure as ferromagnetism does.

Two envelope problems and the roles of ignorance

Four variations on Two Envelope Paradox are stated and compared. The variations are employed to provide a diagnosis and an explanation of what has gone awry in the paradoxical modeling of the decision problem that the paradox poses. The canonical formulation of the paradox underdescribes the ways in which one envelope can have twice the amount that is in the other. Some ways one envelope can have twice the amount that is in the other make it rational to prefer the envelope that was originally rejected. Some do not, and it is a mistake to treat them alike. The nature of the mistake is diagnosed by the different roles that rigid designators and definite descriptions play in unproblematic and in untoward formulations of decision tables that are employed in setting out the decision problem that gives rise to the paradox. The decision maker’s knowledge or ignorance of how one envelope came to have twice the amount that is in the other determines which of the different ways of modeling his decision problem is correct. Under this diagnosis, the paradoxical modeling of the Two Envelope problem is incoherent.

Human behaviour modelled as a statistico-deterministic turing machine

'Free will' and its corollary, the concept of individual responsibility are keystones of the justice system. This paper shows that if we accept a physics that disallows time reversal, the concept of 'free will' is undermined by an integrated understanding of the influence of genetics and environment on human behavioural responses. Analysis is undertaken by modelling life as a novel statistico-deterministic version of a Turing machine, i.e. as a series of transitions between states at successive instants of time. Using this model it is proven by induction that the entire course of life is independent of the action of free will. Although determined by prior state, the probability of transitions between states in response to a standard environmental stimulus is not equal to 1 and the transitions may differ quantitatively at the molecular level and qualitatively at the level of the whole organism. Transitions between states correspond to behaviours. It is shown that the behaviour of identical twins (or clones), although determined, would be incompletely predictable and non-identical, creating an illusion of the operation of 'free will'. 'Free will' is a convenient construct for current judicial systems and social control because it allows rationalization of punishment for those whose behaviour falls outside socially defined norms. Indeed, it is conceivable that maintenance of ideas of free will has co-evolved with community morality to reinforce its operation. If the concept is free will is to be maintained it would require revision of our current physical theories.

The gambling related cognitions scale (GRCS): development, confirmatory factor validation and psychometric properties

Aims The aims of this study are to develop and validate a measure to screen for a range of gambling-related cognitions (GRC) in gamblers. Design and participants A total of 968 volunteers were recruited from a community-based population. They were divided randomly into two groups. Principal axis factoring with varimax rotation was performed on group one and confirmatory factor analysis (CFA) was used on group two to confirm the best-fitted solution. Measurements The Gambling Related Cognition Scale (GRCS) was developed for this study and the South Oaks Gambling Screen (SOGS), the Motivation Towards Gambling Scale (MTGS) and the Depression Anxiety Stress Scale (DASS-2 1) were used for validation. Findings Exploratory factor analysis performed using half the sample indicated five factors, which included interpretative control/bias (GRCS-IB), illusion of control (GRCS-IC), predictive control (GRCS-PC), gambling-related expectancies (GRCS-GE) and a perceived inability to stop gambling (GRCS-IS). These accounted for 70% of the total variance. Using the other half of the sample, CFA confirmed that the five-factor solution fitted the data most effectively. Cronbach's alpha coefficients for the factors ranged from 0.77 to 0.91, and 0.93 for the overall scale. Conclusions This paper demonstrated that the 23-item GRCS has good psychometric properties and thus is a useful instrument for identifying GRC among non-clinical gamblers. It provides the first step towards devising/adapting similar tools for problem gamblers as well as developing more specialized instruments to assess particular domains of GRC.

Do you know where your arm is if you think your head has moved?

Reproduction of a previously presented elbow position is affected by changes in head position. As movement of the head is associated with local biomechanical changes, the aim of the present study was to determine if illusory changes in head position could induce similar effects on the reproduction of elbow position. Galvanic vestibular stimulation (GVS) was applied to healthy subjects in supine lying. The stimulus was applied during the presentation of an elbow position, which the subject then reproduced without stimulation. In the first study, 13 subjects received 1.5 mA stimuli, which caused postural sway in standing, confirming that the firing of vestibular afferents was affected, but no illusory changes in head position were reported. In the second study, 13 subjects received 2.0-3.0 mA GVS. Six out of 13 subjects reported consistent illusory changes in head position, away from the side of the anode. In these subjects, anode right stimulation induced illusory left lateral flexion and elbow joint position error towards extension (p=0.03), while anode left tended to have the opposite effect (p=0.16). The GVS had no effect on error in subjects who did not experience illusory head movement with either 1.5 mA stimulus (p=0.8) or 2.0-3.0 mA stimulus (p=0.7). This study demonstrates that the accuracy of elbow repositioning is affected by illusory changes in head position. These results support the hypothesis that the perceived position of proximal body segments is used in the planning and performance of accurate upper limb movements.

Disrupted cortical proprioceptive representation evokes symptoms of peculiarity, foreignness and swelling, but not pain

Objectives. It has been proposed that disruption of the internal proprioceptive representation, via incongruent sensory input, may underpin pathological pain states, but experimental evidence relies on conflicting visual input, which is not clinically relevant. We aimed to determine the symptomatic effect of incongruent proprioceptive input, imparted by vibration of the wrist tendons, which evokes the illusion of perpetual wrist flexion and disrupts cortical proprioceptive representation. Methods. Twenty-nine healthy and naive volunteers reported symptoms during five conditions: control, active and passive wrist flexion, extensor carpi radialis tendon vibration to evoke illusion of perpetual wrist flexion, and ulnar styloid (sham) vibration. No advice was given about possible illusions. Results. Twenty-one subjects reported the illusion of perpetual wrist flexion during tendon vibration. There was no effect of condition or of whether or not subjects reported an illusion on discomfort/pain (P > 0.28). Peculiarity, swelling and foreignness were greater during tendon vibration than during the other conditions, and greater during tendon vibration in those who reported an illusion of wrist flexion than in those who did not (P < 0.05 for all). Symptoms were reported by at least two subjects in each condition and four subjects reported systemic symptoms (e.g. nausea). Conclusions. In healthy volunteers, incongruent proprioceptive input does not cause discomfort or pain but does evoke feelings of peculiarity, swelling and foreignness in the limb.

The temporal and spatial limits of compensation for fixational eye movements

High-fidelity eye tracking is combined with a perceptual grouping task to provide insight into the likely mechanisms underlying the compensation of retinal image motion caused by movement of the eyes. The experiments describe the covert detection of minute temporal and spatial offsets incorporated into a test stimulus. Analysis of eye motion on individual trials indicates that the temporal offset sensitivity is actually due to motion of the eye inducing artificial spatial offsets in the briefly presented stimuli. The results have strong implications for two popular models of compensation for fixational eye movements, namely efference copy and image-based models. If an efference copy model is assumed, the results place constraints on the spatial accuracy and source of compensation. If an image-based model is assumed then limitations are placed on the integration time window over which motion estimates are calculated. (c) 2006 Elsevier Ltd. All rights reserved.

ENSINO SOCIAL DA CNBB : crítica ao capitalismo neoliberal e ilusão transcendental

A práxis religiosa dos cristãos na América Latina está profundamente associada aos debates de superação da exclusão social na busca de uma sociedade mais justa e solidária. Desde o pós-guerra os cristãos são fundamentais nas ações de transformação da sociedade. Nesta tradição, a CNBB propõe orientações pastorais sobre as diversas realidades da sociedade, também a economia. Entre 1995 e 2004, os documentos oficiais da CNBB apresentam uma contundente crítica ao sistema de globalização neoliberal, apresentando a exigência dos cristãos trabalharem na superação desta ideologia econômica em busca de uma sociedade mais justa e igualitária. É importante perceber as contribuições específicas do cristianismo deste discurso teológico-pastoral. Esta crítica levada a sua radicalidade teológica deve ser capaz de desvelar a ilusão transcendental, criticando a ingenuidade utópica que absolutiza projetos históricos gerando sacrifícios de vidas humanas. Para isto, é necessário contínuo discernimento a partir da liberdade cristã que se constitui em um critério ético fundamental de discernimento a partir da vida das vítimas. Neste sentido, os textos sociais da CNBB são apresentados no contexto do discurso social católico no Brasil, em sua lógica crítica ao neoliberalismo e na análise da ilusão transcendental às vezes reproduzida nas propostas de superação da sociedade atual.

ENTRE A COLONIALIDADE E A LIBERTAÇÃO: UMA ANÁLISE DESCOLONIAL DOS DISCURSOS DAS E SOBRE AS CEB S

Esta tese é uma abordagem dos discursos das e sobre as Comunidades Eclesiais de Base com uma análise de recorte descolonial. O objetivo principal é identificar e mostrar a existência de dois tipos de discursos no interior das Ceb s, sendo um dito e outro não-dito, demonstrando a relevância da experiência concreta para a construção de um discurso mais realista e coerente ao modelo de práxis que as Ceb s propõem. Assim, o problema que a tese tem como objeto é que o discurso supostamente único é na verdade um discurso enunciado enquanto outro discurso foi silenciado. Daí que a não percepção dos dois discursos é indício de que um tipo de discurso é apresentado como o enunciado verdadeiro referente às Ceb s. A partir disto, foram propostos como objetivos específicos identificar os temas fundamentais que aparecem nos discursos da base e dos discursos dos assessores, problematizar estes discursos no cotejamento entre si e demonstrar a relevância da diferença de lugares na tipificação do discurso. A tese segue a formulação de três hipóteses. A hipótese principal é que é possível que o discurso enunciado pelos assessores como referente às Ceb s tenha silenciado o outro discurso não-dito, mas vivido pelo povo da base. Em nível secundário, uma hipótese é de que é possível que subjacente ao discurso apresentado como se fosse único, existam diferenças ligadas ao lugar donde falam os atores e que, por sua vez, influenciam o modo como compreendem a história. Outra hipótese secundária é de que é possível que a colonialidade do poder e do saber esteja presente nos discursos sobre as Ceb s, pois a percepção de discursos distintos é já um indício de crítica que não acede ao apresentado de forma hegemônica como sendo único existente. Para isto, a tese está organizada em quatro capítulos: no primeiro é apresentado o discurso dos assessores, com a identificação e problematização dos temas fundamentais emergentes, no segundo é feito o mesmo com o discurso da base; já no terceiro capítulo são apresentados os conceitos que formam o referencial teórico para a análise e no quarto é feita propriamente a análise descolonial dos discursos.

O LÚDICO VIA FÁBULAS EM ATENDIMENTO PSICOTERAPÊUTICO: UM ESTUDO DE CASO CLÍNICO DE MOBBING

Esta pesquisa verifica a validade da utilização de fábulas em processo psicoterapêutico de paciente de Mobbing acometida de depressão e síndrome de pânico. Desenvolve-se por meio de estudo de caso avaliativo-interventivo evolutivo prolongado, com um total de 116 sessões semanais. Inicialmente realiza o diagnóstico clínico elaborado a partir do desenho da figura humana, extraído do teste projetivo House Tree and Person, de entrevista inicial semi-dirigida, e de coleta de relatos verbais e observações feitas durante os primeiros atendimentos. As sessões são realizadas com utilização ocasional de fábulas, associada ou não a técnicas de relaxamento de Schultz e Jacobson, com interpretação de sonhos e recomendação de filmes. O objetivo é verificar se as fábulas contribuem de forma positiva para o paciente compreender com mais facilidade as interpretações do psicoterapeuta, se diminui sua resistência ao falar dos seus conteúdos e se amplia à consciência simbólica. O primeiro momento interventivo tem a duração de aproximadamente 16 meses, o segundo, de 04 meses, quando é solicitado o segundo desenho e o terceiro processa-se em 09 meses, quando é solicitado o último desenho. No primeiro momento é proporcionado à paciente um ambiente facilitador com sustentação emocional (Holding), buscando resgatar sua ilusão, numa visão winnicottiana. Revela-se uma situação de Mobbing acompanhada de depressão manifesta e síndrome do pânico; com alto nível de exigência pessoal e profissional; grande passividade nos relacionamentos e na dinâmica do casal. Ao final desse momento, já consegue começar a desviar sua auto-agressividade para o meio externo de maneira mais positiva e socialmente aceita. No segundo momento predomina o encontro e aceitação de seu verdadeiro jeito de ser; enxerga o quanto estava se deixando prejudicar; mostra-se mais confiante, comunica-se e enfrenta melhor suas dificuldades afetivas. No terceiro momento demonstra estar segura e feliz. Cuida de sua aparência e sente prazer em ser notada socialmente. Demonstra ter aprendido a se defender em situações de confronto, com maior autonomia e verbaliza estar muito feliz com as mudanças, sorri com freqüência. A análise evolutiva dos desenhos confirmam esta boa evolução. A utilização de fábulas foi muito bem aceita pela paciente, que conseguiu por meio da leitura simbólica contida nas mesmas, aproximar-se de sua problemática e aprender a lidar com ela de forma mais saudável. Os resultados também indicam que a utilização de relaxamento associado à leitura das fábulas contribuiu para sua assimilação mais abrangente e profunda. O estudo ilustra a evolução do caso por meio de 24 vinhetas, devidamente analisadas em relação aos momentos descritos.(AU)

Equivalence of physical and perceived speed in binocular rivalry

The relative dominance of gratings engaged in binocular rivalry can be influenced by their surroundings. One striking example occurs when surrounding motion is congruent with one but not the other grating (C. L. Paffen, S. F. te Pas, R. Kanai, M. J. van der Smagt, & F. A. Verstraten, 2004). However, such center-surround stimulus configurations can also modulate perceived speed, via a directionally tuned process (H. P. Norman, J. F. Norman, J. T. Todd, & D. T. Lindsey, 1996). We recorded rivalry for Gabor patches embedded in a drifting noise texture. Gratings whose directions opposed the background motion tended to dominate more, and vice versa, consistent with previous findings. Observers then matched the speed of a drifting noise-embedded Gabor to that of a Gabor surrounded by mean luminance. Surround motion produced substantial changes in perceived speed, by at least a factor of two for all observers. We then asked whether perceived speed could account for the contextual effects on dominance. We measured the effects of speed on rivalry dominance by changing the physical speeds of rivaling gratings, as determined by the matching data. We found the same pattern of dominance as for the context experiment, indicating that perceived and true speed influence rivalry in the same manner. We propose a Bayesian interpretation of the perceived speed illusion.

Evidence for dissociation between the perceptual and visuomotor systems in humans

When a visual stimulus is continuously moved behind a small stationary window, the window appears displaced in the direction of motion of the stimulus. In this study we showed that the magnitude of this illusion is dependent on (i) whether a perceptual or visuomotor task is used for judging the location of the window, (ii) the directional signature of the stimulus, and (iii) whether or not there is a significant delay between the end of the visual presentation and the initiation of the localization measure. Our stimulus was a drifting sinusoidal grating windowed in space by a stationary, two-dimensional, Gaussian envelope (σ=1 cycle of sinusoid). Localization measures were made following either a short (200 ms) or long (4.2 s) post-stimulus delay. The visuomotor localization error was up to three times greater than the perceptual error for a short delay. However, the visuomotor and perceptual localization measures were similar for a long delay. Our results provide evidence in support of the hypothesis that separate cortical pathways exist for visual perception and visually guided action and that delayed actions rely on stored perceptual information.

Contextual effects in speed perception may occur at an early stage of processing

How does nearby motion affect the perceived speed of a target region? When a central drifting Gabor patch is surrounded by translating noise, its speed can be misperceived over a fourfold range. Typically, when a surround moves in the same direction, perceived centre speed is reduced; for opposite-direction surrounds it increases. Measuring this illusion for a variety of surround properties reveals that the motion context effects are a saturating function of surround speed (Experiment I) and contrast (Experiment II). Our analyses indicate that the effects are consistent with a subtractive process, rather than with speed being averaged over area. In Experiment III we exploit known properties of the motion system to ask where these surround effects impact. Using 2D plaid stimuli, we find that surround-induced shifts in perceived speed of one plaid component produce substantial shifts in perceived plaid direction. This indicates that surrounds exert their influence early in processing, before pattern motion direction is computed. These findings relate to ongoing investigations of surround suppression for direction discrimination, and are consistent with single-cell findings of direction-tuned suppressive and facilitatory interactions in primary visual cortex (V1).

Synapses, quantum theory and panpsychism

The introduction situates the ‘hard problem’ in its historical context and argues that the problem has two sides: the output side (the Kant-Eccles problem of the freedom of the Will) and the input side (the problem of qualia). The output side ultimately reduces to whether quantum mechanics can affect the operation of synapses. A discussion of the detailed molecular biology of synaptic transmission as presently understood suggests that such affects are unlikely. Instead an evolutionary argument is presented which suggests that our conviction of free agency is an evolutionarily induced illusion and hence that the Kant-Eccles problem is itself illusory. This conclusion is supported by well-known neurophysiology. The input side, the problem of qualia, of subjectivity, is not so easily outflanked. After a brief review of the neurophysiological correlates of consciousness (NCC) and of the Penrose-Hameroff microtubular neuroquantology it is again concluded that the molecular neurobiology makes quantum wave-mechanics an unlikely explanation. Instead recourse is made to an evolutionarily- and neurobiologically-informed panpsychism. The notion of an ‘emergent’ property is carefully distinguished from that of the more usual ‘system’ property used by most dual-aspect theorists (and the majority of neuroscientists) and used to support Llinas’ concept of an ‘oneiric’ consciousness continuously modified by sensory input. I conclude that a panpsychist theory, such as this, coupled with the non-classical understanding of matter flowing from quantum physics (both epistemological and scientific) may be the default and only solution to the problem posed by the presence of mind in a world of things.

Face context interferes with local part processing in a prosopagnosic patient

We investigated the role of local and global information on perceptual encoding of faces in patient HJA, who shows prosopagnosia and visual agnosia following occipito-temporal damage. HJA and an age-matched control were tested in a simultaneous matching task which focused on detection of local changes in faces: the inversion of central parts (eyes and mouth) relative to their context (as in the Thatcher illusion). Same-different judgements were made to normal, “thatcherised” and mixed type face pairs. Whole faces (Experiment 1), or face parts (Experiment 2), were presented in upright and inverted orientations. Compared to the control, HJA was severely impaired at matching whole faces, but he improved dramatically when face parts were presented in isolation. This suggests an inhibitory influence of face context on HJAs processing of local parts and a relatively intact ability to process part-based information from a face (when context cannot interfere). Face inversion did not affect HJAs performance. A control experiment (Experiment 3) with non-face stimuli (houses) suggested that the inhibitory influence of context on HJAs performance was restricted to faces. These results indicate that contextual information in a face can have an adverse influence on the processing of local part-based information in prosopagnosia.