Theta oscillations in the medial temporal lobe (MTL) of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous theta generation in the MTL. Although coherence between entorhinal and hippocampal theta activity has been found to influence memory formation, it remains unclear whether these two structures can generate theta independently. In this study we analyzed intracranial electroencephalographic (...) (EEG) recordings from 22 patients with unilateral hippocampal sclerosis undergoing presurgical evaluation prior to resection of the epileptic focus. Using a wavelet-based, frequency-band-specific measure of phase synchronization, we quantified synchrony between 10 different recording sites along the longitudinal axis of the hippocampal formation in the non-epileptic brain hemisphere. We compared EEG synchrony between adjacent recording sites (i) within the entorhinal cortex, (ii) within the hippocampus, and (iii) between the hippocampus and entorhinal cortex. We observed a significant interregional gap in synchrony for the delta and theta band, indicating the existence of independent delta/theta rhythms in different subregions of the human MTL. The interaction of these rhythms could represent the temporal basis for the information processing required for mnemonic encoding and retrieval. (shrink)
Interest shown on the environmental impact of operations of multinational enterprises in developing countries has grown significantly recently, and has fuelled a heated public policy debate. In particular, there has been interest in the environmental degradation of host communities and nations resulting from the operations of multinational oil companies in developing countries. This article examines the issue of environmental costs and responsibilities resulting from oil exploitation and production in the Niger Delta region of Nigeria. The case study is based, in (...) part, upon series of interviews with key stakeholders in the Nigerian oil industry. The article further examines the implications of the current practice and policies of multinational oil companies with respect to environmental impact of oil exploitation. The study’s findings illustrates that it is becoming increasingly apparent to oil companies that pollution prevention pays while pollution does not and under pressure from stakeholder groups, oil companies now routinely incorporate environmental impact assessments into their corporate strategy. (shrink)
Our everyday interactions increasingly involve both embodied face-to-face communication and various forms of mediated and distributed communication such as email, skype, and facebook. In daily face-to-face communications, we are connected in rhythm and synchrony at multiple levels ranging from the moment-by-moment continuity of timed syllables to emergent body and vocal rhythms of pragmatic sense-making. Our human capacity to synchronize with each other may be essential for our survival as social beings. Moving our bodies and voices together in time embodies (...) a potent pragmatic purpose that of being together. In this synchrony of self with other, witnessing and being present become part of each other. There is growing research into how rhythm and synchrony operate in embodied face-to-face interaction and this provides parameters for investigating the relations and differences in how we connect and are socially present in the embodied and distributed settings, and understanding the effect of one setting upon the other. This paper explores the arena of research into rhythm in human interaction, musical and linguistic, with a focus on the movements of body and voice. It draws together salient issues and ideas that would form the basis for a framework of rhythm in embodied interaction. (shrink)
During monitoring of the discourse, the detection of the relevance of incoming lexical information could be critical for its incorporation to update mental representations in memory. Because, in these situations, the relevance for lexical information is defined by abstract rules that are maintained in memory, results critical to understand how an abstract level of knowledge maintained in mind mediates the detection of the lower-level semantic information. In the present study, we propose that neuronal oscillations participate in the detection of relevant (...) lexical information, based on ‘kept in mind’ rules deriving from more abstract semantic information. We tested our hypothesis using an experimental paradigm that restricted the detection of relevance to inferences based on explicit information, thus controlling for ambiguities derived from implicit aspects. We used a categorization task, in which the semantic relevance was previously defined based on the congruency between a kept in mind category (abstract knowledge), and the lexical-semantic information presented. Our results show that during the detection of the relevant lexical information, phase synchronization of neuronal oscillations selectively increases in delta and theta frequency bands during the interval of semantic analysis. These increments were independent of the semantic category maintained in memory, had a temporal profile specific for each subject, and were mainly induced, as they had no effect on the evoked mean global field power. Also, recruitment of an increased number of pairs of electrodes was a robust observation during the detection of semantic contingent words. These results are consistent with the notion that the detection of relevant lexical information based on a particular semantic rule, could be mediated by increasing the global phase synchronization of neuronal oscillations, which may contribute to the recruitment of an extended number of cortical regions. (shrink)
Why do some people have problems “feeling the beat”? Here we report a study into participants with congenital impairments in musical rhythm perception and production. A web-based version of the Montreal Battery of Evaluation of Amusia (MBEA) was used to test a large population and three “dysrhythmic” subjects were identified; they scored below cut-off for the rhythm subtests, but not the pitch subtests. Follow-up testing in the laboratory was conducted to characterize the nature of the deficit. The dysrhythmic (...) individuals differed from control subjects when required to synchronize their tapping to an external stimulus with a metrical pulse, but not when required to tap spontaneously (with no external stimulus) or tap in time to an isochronous stimulus. They exhibited a general tendency to perform at half the expected tempo when asked to synchronize to the beat of strongly metrical rhythms. These results suggest that dysrhythmic individuals studied here did not have motor production problems, but suffer a selective rhythm perception deficit that influences the ability to entrain to metrical rhythms. (shrink)
Brain rhythms are more than just passive phenomena in visual cortex. For the first time, we show that the physiology underlying brain rhythms actively suppresses and releases cortical areas on a second-to-second basis during visual processing. Furthermore, their influence is specific at the scale of individual gyri. We quantified the interaction between broadband spectral change and brain rhythms on a second-to-second basis in electrocorticographic (ECoG) measurement of brain surface potentials in five human subjects during a visual search task. Comparison of (...) visual search epochs with a blank screen baseline revealed changes in the raw potential, the amplitude of rhythmic activity, and in the decoupled broadband spectral amplitude. We present new methods to characterize the intensity and preferred phase of coupling between broadband power and band-limited rhythms, and to estimate the magnitude of rhythm-to-broadband modulation on a trial-by-trial basis. These tools revealed numerous coupling motifs between the phase of low frequency (δ, θ, α, β, and γ band) rhythms and the amplitude of broadband spectral change. In the θ and β ranges, the coupling of phase to broadband change is dynamic during visual processing, decreasing in some occipital areas and increasing in others, in a gyrally specific pattern. Finally, we demonstrate that the rhythms interact with one another across frequency ranges, and across cortical sites. (shrink)
Technological progress in computer science and neuroimaging has resulted in many approaches that aim to detect brain states and translate them to an external output. Studies from the field of brain-computer interfaces and neurofeedback have validated the coupling between brain signals and computer devices; however a cognitive model of the processes involved remains elusive. Psychological parameters usually play a moderate role in predicting the performance of brain-computer interface (BCI) and neurofeedback (NF) users. The concept of a locus of control, i.e. (...) whether one’s own action is determined by internal or external causes, may help to unravel inter-individual performance capacities. Here, we present data from twenty healthy participants who performed a feedback task based on EEG recordings of the sensorimotor rhythm (SMR). One group of ten participants underwent ten training sessions where the amplitude of the SMR was coupled to a vertical feedback bar. The other group of ten participants participated in the same task but relied on sham feedback. Our analysis revealed that a locus of control score focusing on control beliefs with regard to technology negatively correlated with the power of SMR. These preliminary results suggest that participants whose confidence in control over technical devices is high might consume additional cognitive resources. This higher effort in turn may interfere with brain states of relaxation as reflected in the SMR. As a consequence, one way to improve control over brain signals in neurofeedback paradigms may be to explicitly instruct users not to force mastery but instead to aim at a state of effortless relaxation. (shrink)
The Dirac δ function has solid roots in nineteenth century work in Fourier analysis and singular integrals by Cauchy and others, anticipating Dirac’s discovery by over a century, and illuminating the nature of Cauchy’s infinitesimals and his infinitesimal definition of δ.
The combination of corporate-community conflicts and oil transnational corporations' (TNCs) rhetoric about being socially responsible has meant that the issue of community development and poverty reduction have recently moved from the periphery to the heart of strategic business thinking within the Nigerian oil industry. As a result, oil TNCs have increasingly responded to this challenge by adopting partnership strategies as a means to contribute to poverty reductions in their host communities as well as secure their social licence to operate. This (...) paper critically examines the strengths and weaknesses of the different community development partnership (CDPs) initiatives employed by Shell, Exxon Mobil and Total to contribute to poverty reduction within their host communities in the Niger Delta, Nigeria. Drawing on empirical data and critical analysis, the paper argues that while the CDP initiatives by SPDC, MPN and EPNL have the potential to contribute to community development, the failure to integrate negative injunction duties into existing partnerships means that the partnerships make no difference to how oil TNCs conduct their core business operation. Consequently, CDPs have had limited positive impact on poverty reduction in the Niger Delta. The paper concludes by examining the implications of the emerging issues for partnership and poverty reduction. (shrink)
This article develops a dynamic account of rhythm as ‘order-in-movement’ that opposes static accounts of rhythm as abstract time, as essentially a pattern of possibly unstressed sounds and silences. This dynamic account is humanistic: it focuses on music as a humanly-produced, sonorous phenomenon, privileging the human as opposed to the abstract, or the organic or mechanical. It defends the claim that movement is the most fundamental conceptualization of music—the basic category in terms of which it is experienced—and suggests, (...) against Scruton, that music literally and not merely metaphorically moves. (shrink)
This article briefly introduces a new argument concerning corporate social responsibility, based in an analysis of values expressed by the recent and contemporary liberal economists Milton Friedman and Michael Jensen. I will provide the gist of the argument by considering implications of Friedman’s very familiar view, that “…there is one and only one social responsibility of business - to use its resources and engage in activities to increase its profits so long as it stays within the rules of the game.” (...) Harvard professor Michael Jensen has argued from slightly different premises to a similar conclusion, that “social welfare is maximized when all firms in an economy attempt to maximize their own total firm value.” Vestiges of such influential argument are also easily spotted in American corporate culture (See Palmer, 2007). I suggest that these authors’ positions allow for possibilities that undermine their broader fundamental values, however. I will concentate especially on Friedman’s classic treatment of liberal politics and capitalist economics, Capitalism and Freedom, in which he alludes to the importance of accepting and promoting individual freedom. Such values demand governmental and social stability, and so, in some cases, particularly where business activity may destabilize society, it would appear that freedom may be seriously threatened by corporate activity that follows Friedman’s narrow prescription. Nowhere is this more evident, at present, than in the Niger River Delta, where the promise and profits of oil have produced a society in great disarray. A case study of the delta situation indicates the problems of the narrow view of business goals and business responsibility, and this article will go on to consider possible solutions to those problems that delineate general sorts of responsibilities. The solutions require corporations to take a much broader view of their activity: I suggest that Friedman’s flaw reflects a general weakness of liberal individualism, nicely exposed in Amartya Sen’s arguments that lead to the conclusion that, “we have to see individual freedom as a social commitment.” That social commitment includes the goal of promoting individual freedom, but reaching for the goal may proceed along lines that are not so narrowly economic as Friedman would have, indicating new roles for business and government cooperation even in less extreme cases than that of the Niger Delta. (shrink)
Perception of temporal patterns is fundamental to normal hearing, speech, motor control, and music. Certain types of pattern understanding are unique to humans, such as musical rhythm. Although human responses to musical rhythm are universal, there is much we do not understand about how rhythm is processed in the brain. Here, I consider findings from research into basic timing mechanisms and models through to the neuroscience of rhythm and meter. A network of neural areas, including motor (...) regions, is regularly implicated in basic timing as well as processing of musical rhythm. However, fractionating the specific roles of individual areas in this network has remained a challenge. Distinctions in activity patterns appear between "automatic" and "cognitively controlled" timing processes, but the perception of musical rhythm requires features of both automatic and controlled processes. In addition, many experimental manipulations rely on participants directing their attention toward or away from certain stimulus features, and measuring corresponding differences in neural activity. Many temporal features, however, are implicitly processed whether attended to or not, making it difficult to create controlled baseline conditions for experimental comparisons. The variety of stimuli, paradigms, and definitions can further complicate comparisons across domains or methodologies. Despite these challenges, the high level of interest and multitude of methodological approaches from different cognitive domains (including music, language, and motor learning) have yielded new insights and hold promise for future progress. (shrink)
Some proponents of the pro-life movement argue against morning after pills, IUDs, and contraceptive pills on grounds of a concern for causing embryonic death. What has gone unnoticed, however, is that the pro-life line of argumentation can be extended to the rhythm method of contraception as well. Given certain plausible empirical assumptions, the rhythm method may well be responsible for a much higher number of embryonic deaths than some other contraceptive techniques.
Decision-making deficits in clinical populations are often assessed with the Iowa gambling task (IGT). Performance on this task is driven by latent psychological processes, the assessment of which requires an analysis using cognitive models. Two popular examples of such models are the Expectancy Valence (EV) and Prospect Valence Learning (PVL) models. These models have recently been subjected to sophisticated procedures of model checking, spawning a hybrid version of the EV and PVL models—the PVL-Delta model. In order to test the validity (...) of the PVL-Delta model we present a parameter space partitioning (PSP) study and a test of selective influence. The PSP study allows one to assess the choice patterns that the PVL-Delta model generates across its entire parameter space. The PSP study revealed that the model accounts for empirical choice patterns featuring a preference for the good decks or the decks with infrequent losses; however, the model fails to account for empirical choice patterns featuring a preference for the bad decks. The test of selective influence investigates the effectiveness of experimental manipulations designed to target only a single model parameter. This test showed that the manipulations were successful for all but one parameter. To conclude, despite a few shortcomings, the PVL-Delta model seems to be a better IGT model than the popular EV and PVL models. (shrink)
Although it provides a useful description of elementary movement trajectories, we argue that the delta-lognormal model is deficient as an account of speed/accuracy tradeoffs in aimed movements. It fails in this regard because (1) it is deterministic, (2) its formulation ignores critical task elements, and (3) it fails to account for the corrective role of submovements.
The focus of this paper is Derrida's idea of rhythm. I will analyse how the idea of rhythm can work in a contemporary semiotic, and in particular in a semiotic of interpretation, in order to eliminate the confusion between interpretation and semantics and to constitute a syntactic model of interpretation. In ‘The Double Session’ Derrida uses the Greek word rytmos in order to indicate the ‘law of spacing’. Rytmos is a form that is always about to change or (...) to break up, because it is not a definitive form. It is a not-proper form. But when I say here that a rhythmic relation is a not-proper form, the word ‘proper’ is intended in the sense of Heidegger's Eigentlichkeit. In this sense a not-proper relation is a relation which is not grounded on a justification. What I'm trying to demonstrate in this essay is that the rhythmic relation discovers another sense of the word ‘proper’, another meaning, which is far from Heidegger's Eigentlichkeit. In this sense, it is possible to say that the problem of a rhythmic relation is the problem of a relation between ‘two’ that is not justified by the third element which makes it proper or eigentlich. (shrink)
Rhythm should be regarded as a perceptional category rather than as a property of the work of art. Rhythm might be classified according to three principles, serial rhythm, sequential rhythm and dynamic rhythm, three basic sets of gestalt qualities that lay the foundation for versification systems.Two schemas decide the rhythm of a poem: direction and balance. ‘Direction’ refers to rising and falling movements in the line. ‘Balance’ refers to repetitions in a play between symmetry (...) and asymmetry as well as a moment of rest.Rhythms produce meaning, probably due to the fact that rhythms activate internalized bodily experiences as well as conventional meaning patterns. This is demonstrated on the basis of a poem by Sylvia Plath. (shrink)
The books translated in this volume are fourth, fifth, and sixth in the traditional ordering of Aristotle's Metaphysics. The nature and scope of metaphysics are discussed in gamma and epsilon. A subtle examination of the principles of non-contradiction and excluded middle occupies the latter part of gamma. Delta is in the form of a philosophical lexicon. All three books contain important material on being, substance, `accident', unity, truth, cause, and other such concepts. The translation is very close to the Greek, (...) as an aid to students who cannot check the English version against the original. It is followed by an interpretative and critical commentary. For this new edition Mr Kirwan has added a substantial section of further comment on several central issues, and considerably expanded the bibliography. (shrink)
The weaver ant, Oecophylla smaragdina Fabricius (Hymenoptera: Formicidae), has long been known as perhaps the first example of human manipulation of a natural predator population to enhance the natural biological control of insect pests. The practice of ant husbandry in Vietnamese citrus orchards and the knowledge associated with the use of weaver ants in the Mekong delta are described. In contrast to other regions of Asia, where weaver ants are noted for their role in the protection of citrus from insect (...) damage, citrus farmers in the Mekong delta explain the benefits of ant husbandry in terms of an improvement in fruit quality, likened to the influence of fertilizers, that occurs in direct response to excretory products deposited by the weaver ants as they patrol the fruit. A series of tests, carried out in 1993–94, rated the external shine, sweetness, juiciness, and overall appeal, as characteristics of fruit quality, for paired comparisons of sweet orange, mandarin, and pummelo fruit that had been grown in the presence of weaver ants or from which ants had been excluded. The tests indicate a strong influence of the presence of the weaver ant on external shine, juiciness, and overall appeal for each of the citrus fruits, but particularly for mandarin. The significance of these results and ant husbandry practices in the Mekong delta are discussed in relation to the development of citrus production in Vietnam. (shrink)
Children’s play is widely believed by educators and social scientists to have a training function that contributes to psychosocial development as well as the acquisition of skills related to adult competency in task performance. In this paper we examine these assumptions from the perspective of life-history theory using behavioral observation and household economic data collected among children in a community in the Okavango Delta of Botswana where people engage in mixed subsistence regimes of dry farming, foraging, and herding.We hypothesize that (...) if play contributes to adult competency then time allocation to play will decrease as children approach adult levels of competence. This hypothesis generates the following predictions: (1) time allocated to play activities that develop specific productive skills should decline in relation to the proportion of adult competency achieved; (2) children will spend more time in forms of play that are related to skill development in tasks specific to the subsistence ecology in which that child participates or expects to participate; and (3) children will spend more time in forms of play that are related to skill development in tasks clearly related to the gender-specific productive role in the subsistence ecology in which that child participates or expects to participate.We contrast these expectations with the alternative hypothesis that if play is not preparatory for adult competence then time allocated to each play activity should diminish at the same rate. This latter hypothesis generates the following two predictions: (1) time allocation to play should be unaffected by subsistence regime and (2) patterns of time allocation to play should track patterns of growth and energy balance.Results from multiple regression analysis support earlier research in this community showing that trade-offs between immediate productivity and future returns were a primary determinant of children’s activity patterns. Children whose labor was in greater demand spent significantly less time playing. In addition, controlling for age and gender, children spent significantly more time in play activities related to tasks specific to their household subsistence economy. These results are consistent with the assertion that play is an important factor in the development of adult competency and highlight the important contributions of an evolutionary ecological perspective in understanding children’s developmental trajectories. (shrink)
The aim of this study was to explore the role of attention in pulse and meter perception using complex rhythms. We used a selective attention paradigm in which participants attended to either a complex auditory rhythm or a visually presented word list. Performance on a reproduction task was used to gauge whether participants were attending to the appropriate stimulus. We hypothesized that attention to complex rhythms – which contain no energy at the pulse frequency – would lead to activations (...) in motor areas involved in pulse perception. Moreover, because multiple repetitions of a complex rhythm are needed to perceive a pulse, activations in pulse related areas would be seen only after sufficient time had elapsed for pulse perception to develop. Selective attention was also expected to modulate activity in sensory areas specific to the modality. We found that selective attention to rhythms led to increased BOLD responses in basal ganglia, and basal ganglia activity was observed only after the rhythms had cycled enough times for a stable pulse percept to develop. These observations suggest that attention is needed to recruit motor activations associated with the perception of pulse in complex rhythms. Moreover, attention to the auditory stimulus enhanced activity in an attentional sensory network including primary auditory, insula, anterior cingulate, and prefrontal cortex, and suppressed activity in sensory areas associated with attending to the visual stimulus. (shrink)
In  it is shown that only using exponentiation can one prove the existence of non trivial solutions of Pell equations in I$\Delta_0$. However, in this paper we will prove that any Pell equation has a non trivial solution modulo m for every m in I$\Delta_0$.
We examine the action of unary $\Delta^0_2$ functions on the regressive isols. A manageable theory is produced and we find that such a function maps $\Lambda_R$ into $\Lambda$ if and only if it is eventually $R\uparrow$ increasing and maps $\Lambda_R$ into $\Lambda_R$ if and only if it is eventually recursive increasing. Our paper concludes with a discussion of other methods for extending functions to $\Lambda_R$.