1,954 research outputs found

    Childhood maltreatment and adult psychopathology: pathways to hypothalamic-pituitary-adrenal axis dysfunction

    Get PDF
    OBJECTIVE: The aim of this paper was to examine the relationship between childhood maltreatment and adult psychopathology, as reflected in hypothalamic-pituitary-adrenal axis dysfunction. METHOD: A selective review of the relevant literature was undertaken in order to identify key and illustrative research findings. RESULTS: There is now a substantial body of preclinical and clinical evidence derived from a variety of experimental paradigms showing how early-life stress is related to hypothalamic-pituitary-adrenal axis function and psychological state in adulthood, and how that relationship can be modulated by other factors. DISCUSSION: The risk for adult psychopathology and hypothalamic-pituitary-adrenal axis dysfunction is related to a complex interaction among multiple experiential factors, as well as to susceptibility genes that interact with those factors. Although acute hypothalamic-pituitary-adrenal axis responses to stress are generally adaptive, excessive responses can lead to deleterious effects. Early-life stress alters hypothalamic-pituitary-adrenal axis function and behavior, but the pattern of hypothalamic-pituitary-adrenal dysfunction and psychological outcome in adulthood reflect both the characteristics of the stressor and other modifying factors. CONCLUSION: Research to date has identified multiple determinants of the hypothalamic-pituitary-adrenal axis dysfunction seen in adults with a history of childhood maltreatment or other early-life stress. Further work is needed to establish whether hypothalamic-pituitary-adrenal axis abnormalities in this context can be used to develop risk endophenotypes for psychiatric and physical illnesses.OBJETIVO: A meta deste artigo foi a de estudar as relações ente maus-tratos na infância e psicopatologia no adulto, como reflexo de uma disfunção do eixo hipotálamo-pituitária-adrenal. MÉTODO: Uma revisão seletiva da literatura relevante foi feita para identificar achados-chave e ilustrativos. RESULTADOS: Existe atualmente um volume significativo de achados científicos pré-clínicos e clínicos derivados de paradigmas experimentais, que demonstram que o estresse precoce está relacionado à função do eixo hipotálamo-pituitária-adrenal e a estados psicológicos no indivíduo adulto, e como esta relação pode ser modulada por outros fatores. DISCUSSÃO: O risco para o desenvolvimento de psicopatologia no adulto e disfunções do eixo hipotálamo-pituitária-adrenal está relacionado à complexa interação de múltiplos fatores vivenciais, assim como a genes que levam a uma susceptibilidade, que interagem com estes fatores. Embora as respostas agudas do eixo hipotálamo-pituitária-adrenal sejam geralmente adaptativas, as respostas excessivas podem levar a efeitos deletérios. O estresse precoce pode alterar a função do eixo hipotálamo-pituitária-adrenal assim como o comportamento, porém, o padrão da disfunção do eixo hipotálamo-pituitária-adrenal e a evolução psicológica na vida adulta refletem ambas as características do estressor e outros fatores modificadores. CONCLUSÃO: A pesquisa atual identificou múltiplos determinantes da disfunção do eixo hipotálamo-pituitária-adrenal encontrados em adultos com história de maus-tratos na infância ou outros estressores precoces. Trabalhos futuros são necessários para estabelecer se as anormalidades do eixo hipotálamo-pituitária-adrenal neste contexto podem ser usadas para o desenvolvimento de endofenótipos de risco para doenças físicas ou psiquiátricas.Universidade Federal de São Paulo (UNIFESP) Instituto PROVEBrown University Warren Alpert Medical School Butler HospitalUNIFESP, Instituto PROVESciEL

    Acceleressence: Dark Energy from a Phase Transition at the Seesaw Scale

    Full text link
    Simple models are constructed for "acceleressence" dark energy: the latent heat of a phase transition occurring in a hidden sector governed by the seesaw mass scale v^2/M_Pl, where v is the electroweak scale and M_Pl the gravitational mass scale. In our models, the seesaw scale is stabilized by supersymmetry, implying that the LHC must discover superpartners with a spectrum that reflects a low scale of fundamental supersymmetry breaking. Newtonian gravity may be modified by effects arising from the exchange of fields in the acceleressence sector whose Compton wavelengths are typically of order the millimeter scale. There are two classes of models. In the first class the universe is presently in a metastable vacuum and will continue to inflate until tunneling processes eventually induce a first order transition. In the simplest such model, the range of the new force is bounded to be larger than 25 microns in the absence of fine-tuning of parameters, and for couplings of order unity it is expected to be \approx 100 microns. In the second class of models thermal effects maintain the present vacuum energy of the universe, but on further cooling, the universe will "soon" smoothly relax to a matter dominated era. In this case, the range of the new force is also expected to be of order the millimeter scale or larger, although its strength is uncertain. A firm prediction of this class of models is the existence of additional energy density in radiation at the eV era, which can potentially be probed in precision measurements of the cosmic microwave background. An interesting possibility is that the transition towards a matter dominated era has occurred in the very recent past, with the consequence that the universe is currently decelerating.Comment: 10 pages, references adde

    3D simulations of linearized scalar fields in Kerr spacetime

    Get PDF
    We investigate the behavior of a dynamical scalar field on a fixed Kerr background in Kerr-Schild coordinates using a 3+1 dimensional spectral evolution code, and we measure the power-law tail decay that occurs at late times. We compare evolutions of initial data proportional to f(r) Y_lm(theta,phi) where Y_lm is a spherical harmonic and (r,theta,phi) are Kerr-Schild coordinates, to that of initial data proportional to f(r_BL) Y_lm(theta_BL,phi), where (r_BL,theta_BL) are Boyer-Lindquist coordinates. We find that although these two cases are initially almost identical, the evolution can be quite different at intermediate times; however, at late times the power-law decay rates are equal.Comment: 12 pages, 9 figures, revtex4. Major revision: added figures, added subsection on convergence, clarified discussion. To appear in Phys Rev

    An exploration of lifestyle beliefs and lifestyle behaviour following stroke: findings from a focus group study of patients and family members

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Stroke is a major cause of disability and family disruption and carries a high risk of recurrence. Lifestyle factors that increase the risk of recurrence include smoking, unhealthy diet, excessive alcohol consumption and physical inactivity. Guidelines recommend that secondary prevention interventions, which include the active provision of lifestyle information, should be initiated in hospital, and continued by community-based healthcare professionals (HCPs) following discharge. However, stroke patients report receiving little/no lifestyle information.</p> <p>There is a limited evidence-base to guide the development and delivery of effective secondary prevention lifestyle interventions in the stroke field. This study, which was underpinned by the Theory of Planned Behaviour, sought to explore the beliefs and perceptions of patients and family members regarding the provision of lifestyle information following stroke. We also explored the influence of beliefs and attitudes on behaviour. We believe that an understanding of these issues is required to inform the content and delivery of effective secondary prevention lifestyle interventions.</p> <p>Methods</p> <p>We used purposive sampling to recruit participants through voluntary sector organizations (29 patients, including 7 with aphasia; 20 family members). Using focus group methods, data were collected in four regions of Scotland (8 group discussions) and were analysed thematically.</p> <p>Results</p> <p>Although many participants initially reported receiving no lifestyle information, further exploration revealed that most had received written information. However, it was often provided when people were not receptive, there was no verbal reinforcement, and family members were rarely involved, even when the patient had aphasia. Participants believed that information and advice regarding healthy lifestyle behaviour was often confusing and contradictory and that this influenced their behavioural intentions. Family members and peers exerted both positive and negative influences on behavioural patterns. The influence of HCPs was rarely mentioned. Participants' sense of control over lifestyle issues was influenced by the effects of stroke (e.g. depression, reduced mobility) and access to appropriate resources.</p> <p>Conclusions</p> <p>For secondary prevention interventions to be effective, HCPs must understand psychological processes and influences, and use appropriate behaviour change theories to inform their content and delivery. Primary care professionals have a key role to play in the delivery of lifestyle interventions.</p

    An ultraviolet-optical flare from the tidal disruption of a helium-rich stellar core

    Get PDF
    The flare of radiation from the tidal disruption and accretion of a star can be used as a marker for supermassive black holes that otherwise lie dormant and undetected in the centres of distant galaxies. Previous candidate flares have had declining light curves in good agreement with expectations, but with poor constraints on the time of disruption and the type of star disrupted, because the rising emission was not observed. Recently, two `relativistic' candidate tidal disruption events were discovered, each of whose extreme X-ray luminosity and synchrotron radio emission were interpreted as the onset of emission from a relativistic jet. Here we report the discovery of a luminous ultraviolet-optical flare from the nuclear region of an inactive galaxy at a redshift of 0.1696. The observed continuum is cooler than expected for a simple accreting debris disk, but the well-sampled rise and decline of its light curve follows the predicted mass accretion rate, and can be modelled to determine the time of disruption to an accuracy of two days. The black hole has a mass of about 2 million solar masses, modulo a factor dependent on the mass and radius of the star disrupted. On the basis of the spectroscopic signature of ionized helium from the unbound debris, we determine that the disrupted star was a helium-rich stellar core.Comment: To appear in Nature on May 10, 201

    Observational and Dynamical Characterization of Main-Belt Comet P/2010 R2 (La Sagra)

    Full text link
    We present observations of comet-like main-belt object P/2010 R2 (La Sagra) obtained by Pan-STARRS 1 and the Faulkes Telescope-North on Haleakala in Hawaii, the University of Hawaii 2.2 m, Gemini-North, and Keck I telescopes on Mauna Kea, the Danish 1.54 m telescope at La Silla, and the Isaac Newton Telescope on La Palma. An antisolar dust tail is observed from August 2010 through February 2011, while a dust trail aligned with the object's orbit plane is also observed from December 2010 through August 2011. Assuming typical phase darkening behavior, P/La Sagra is seen to increase in brightness by >1 mag between August 2010 and December 2010, suggesting that dust production is ongoing over this period. These results strongly suggest that the observed activity is cometary in nature (i.e., driven by the sublimation of volatile material), and that P/La Sagra is therefore the most recent main-belt comet to be discovered. We find an approximate absolute magnitude for the nucleus of H_R=17.9+/-0.2 mag, corresponding to a nucleus radius of ~0.7 km, assuming an albedo of p=0.05. Using optical spectroscopy, we find no evidence of sublimation products (i.e., gas emission), finding an upper limit CN production rate of Q_CN<6x10^23 mol/s, from which we infer an H2O production rate of Q_H2O<10^26 mol/s. Numerical simulations indicate that P/La Sagra is dynamically stable for >100 Myr, suggesting that it is likely native to its current location and that its composition is likely representative of other objects in the same region of the main belt, though the relatively close proximity of the 13:6 mean-motion resonance with Jupiter and the (3,-2,-1) three-body mean-motion resonance with Jupiter and Saturn mean that dynamical instability on larger timescales cannot be ruled out.Comment: 23 pages, 13 figures, accepted for publication in A

    Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

    Get PDF
    Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship
    corecore