Fermion-Boson Interactions and Quantum Algebras

Quantum Algebras (q-algebras) are used to describe interactions between fermions and bosons. Particularly, the concept of a su_q(2) dynamical symmetry is invoked in order to reproduce the ground state properties of systems of fermions and bosons interacting via schematic forces. The structure of the proposed su_q(2) Hamiltonians, and the meaning of the corresponding deformation parameters, are discussed.Comment: 20 pages, 10 figures. Physical Review C (in press

Modo borderline e mundo do trabalho: um ensaio sobre implicações e perspectivas atuais

Resumo Partindo do pressuposto de que o modo border line parece constituir uma nova "normalidade" atualmente, este artigo busca discutir a sociedade contemporânea em seus modos de vida e o impacto sobre o mundo do trabalho. A busca constante pelo sucesso e pela realização profissional atravessa, consequentemente, as relações de trabalho, que constituem o sujeito. Não há tempo para vazios! É preciso produzir. Considera-se para a discussão o que chamamos de "modo borderline", pensado a partir de sua dimensão fenomenológica e não estrutural, portanto, não a partir do paradigma da psicopatologia individual, mas como sintoma da cultura, em uma sociedade marcada pela im pulsividade, fragilidade dos laços sociais e pela chamada "cultura do narcisismo". Através de uma abordagem psicanalítica e com breve descrição da evolução dos modos de trabalho e produção ao longo dos anos, propõe-se uma discussão a respeito dessas novas configurações de vida implicadas no mundo do trabalho, pensando, sobretudo, em como se dá essa relação na contemporaneidade, em pleno capitalismo flexível

Altered oscillatory brain dynamics after repeated traumatic stress

Kolassa I-T, Wienbruch C, Neuner F, et al. Altered oscillatory brain dynamics after repeated traumatic stress. BMC Psychiatry. 2007;7(1): 56.BACKGROUND: Repeated traumatic experiences, e.g. torture and war, lead to functional and structural cerebral changes, which should be detectable in cortical dynamics. Abnormal slow waves produced within circumscribed brain regions during a resting state have been associated with lesioned neural circuitry in neurological disorders and more recently also in mental illness. METHODS: Using magnetoencephalographic (MEG-based) source imaging, we mapped abnormal distributions of generators of slow waves in 97 survivors of torture and war with posttraumatic stress disorder (PTSD) in comparison to 97 controls. RESULTS: PTSD patients showed elevated production of focally generated slow waves (1-4 Hz), particularly in left temporal brain regions, with peak activities in the region of the insula. Furthermore, differential slow wave activity in right frontal areas was found in PTSD patients compared to controls. CONCLUSION: The insula, as a site of multimodal convergence, could play a key role in understanding the pathophysiology of PTSD, possibly accounting for what has been called posttraumatic alexithymia, i.e., reduced ability to identify, express and regulate emotional responses to reminders of traumatic events. Differences in activity in right frontal areas may indicate a dysfunctional PFC, which may lead to diminished extinction of conditioned fear and reduced inhibition of the amygdala

Fact or Factitious? A Psychobiological Study of Authentic and Simulated Dissociative Identity States

BACKGROUND: Dissociative identity disorder (DID) is a disputed psychiatric disorder. Research findings and clinical observations suggest that DID involves an authentic mental disorder related to factors such as traumatization and disrupted attachment. A competing view indicates that DID is due to fantasy proneness, suggestibility, suggestion, and role-playing. Here we examine whether dissociative identity state-dependent psychobiological features in DID can be induced in high or low fantasy prone individuals by instructed and motivated role-playing, and suggestion. METHODOLOGY/PRINCIPAL FINDINGS: DID patients, high fantasy prone and low fantasy prone controls were studied in two different types of identity states (neutral and trauma-related) in an autobiographical memory script-driven (neutral or trauma-related) imagery paradigm. The controls were instructed to enact the two DID identity states. Twenty-nine subjects participated in the study: 11 patients with DID, 10 high fantasy prone DID simulating controls, and 8 low fantasy prone DID simulating controls. Autonomic and subjective reactions were obtained. Differences in psychophysiological and neural activation patterns were found between the DID patients and both high and low fantasy prone controls. That is, the identity states in DID were not convincingly enacted by DID simulating controls. Thus, important differences regarding regional cerebral bloodflow and psychophysiological responses for different types of identity states in patients with DID were upheld after controlling for DID simulation. CONCLUSIONS/SIGNIFICANCE: The findings are at odds with the idea that differences among different types of dissociative identity states in DID can be explained by high fantasy proneness, motivated role-enactment, and suggestion. They indicate that DID does not have a sociocultural (e.g., iatrogenic) origin

Anterior cingulate cortical thickness is a stable predictor of recovery from post-traumatic stress disorder

BackgroundDecreased cortical thickness in frontal and temporal regions has been observed in individuals suffering from post-traumatic stress disorder (PTSD), compared to healthy controls and trauma-exposed participants without PTSD. In addition, individual differences, both functional and structural, in the anterior cingulate cortex (ACC) have been shown to predict symptom severity reduction. Although there is some evidence suggesting that activity in this region changes as a function of recovery, it remains unknown whether there are any structural correlates of recovery from PTSD.MethodThirty participants suffering from moderate to severe PTSD underwent a magnetic resonance imaging (MRI) scan following an initial clinical assessment. A second assessment took place 6–9 months later. In addition, a subgroup of 25 participants completed a second MRI scan at that time. PTSD symptom severity changes over time were regressed against vertex-based cortical thickness.ResultsWe found that cortical thickness in the right subgenual ACC (sgACC) predicted symptom improvement. Moreover, cortical thickness within this region of the ACC, measured 6–9 months later (n = 25), was also correlated with the same measure of symptom improvement. By contrast, no relationship was found between change in cortical thickness in this area and current PTSD symptom levels or degree of recovery.ConclusionsOur results suggest that sgACC thickness may be a stable marker of recovery potential in PTSD.</jats:sec