7,866 research outputs found

    World history and world outlook

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    La historia mundial es una forma particularmente adecuada para hacer frente al etnocentrismo. Los textos sobre historia general existentes hasta la fecha mencionan a China en uno o dos capítulos, mientras que dedican el resto de su tiempo a Europa. ¿Es esto debido a que solo Europa ha cambiado, a que solo han tenido lugar acontecimientos en Europa? Cualquiera que haya estudiado la historia de China le dirá que esto no es cierto. La historia de la cultura china es para la humanidad mundial moderna prácticamente tan importante, desde un punto de vista internacional, como lo es la historia de Europa. Sin embargo, cuando leemos “historia mundial”, leemos principalmente sobre Europa.World history has a value in breaking down our ethnocentrism. The up-to-date general histories mention China in one or two chapters, whereas they spend all the rest of their time on Europe. Is this because only Europe has changed, only Europe has had things happen? Anyone who has studied the history of China will tell you this is not true. The history of Chinese culture is as important, from an international point of view, to modern world humanity as is the history of Europe. Yet when we read “world history” we read chiefly of Europe

    Learning From Early Attempts to Generalize Darwinian Principles to Social Evolution

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    Copyright University of Hertfordshire & author.Evolutionary psychology places the human psyche in the context of evolution, and addresses the Darwinian processes involved, particularly at the level of genetic evolution. A logically separate and potentially complementary argument is to consider the application of Darwinian principles not only to genes but also to social entities and processes. This idea of extending Darwinian principles was suggested by Darwin himself. Attempts to do this appeared as early as the 1870s and proliferated until the early twentieth century. But such ideas remained dormant in the social sciences from the 1920s until after the Second World War. Some lessons can be learned from this earlier period, particularly concerning the problem of specifying the social units of selection or replication

    Predictive learning, prediction errors, and attention: evidence from event-related potentials and eye tracking

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    Prediction error (‘‘surprise’’) affects the rate of learning: We learn more rapidly about cues for which we initially make incorrect predictions than cues for which our initial predictions are correct. The current studies employ electrophysiological measures to reveal early attentional differentiation of events that differ in their previous involvement in errors of predictive judgment. Error-related events attract more attention, as evidenced by features of event-related scalp potentials previously implicated in selective visual attention (selection negativity, augmented anterior N1). The earliest differences detected occurred around 120 msec after stimulus onset, and distributed source localization (LORETA) indicated that the inferior temporal regions were one source of the earliest differences. In addition, stimuli associated with the production of prediction errors show higher dwell times in an eyetracking procedure. Our data support the view that early attentional processes play a role in human associative learning

    A Novel Medical Treatment of Cushing's Due to Ectopic ACTH in a Patient With Neurofibromatosis Type 1

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    A 64-year-old male presented with neurofibromatosis 1 and Cushing's syndrome. Clinically he was over weight, depressed with extensive skin bruising and hypertension. His 24 hours urinary metanephrines, urinary 5HIAA, gut peptides and chromgranin levels were normal. His renal function and renal MRI scan was also normal. His cortisol failed to suppress on overnight dexamethsone suppression test. His low dose dexamethasone suppression with CRH stimulation showed failure of suppression of cortisol to < 50 nmol/L and ACTH was measurable at 10 ng/L on day 3. There was no response of ACTH or cortisol to CRH stimulation. His ACTH precursors were high at 126 pmol/L consistent with defective pro-opiomelanocortin (POMC) processing suggesting an ectopic source of ACTH production. The MRI scan of his pituitary and CT scan of the adrenal glands was normal. His octreotide scan was negative. The source of his ectopic ACTH was most likely a large retroperitoneal plexiform neurofibroma seen on CT abdomen that had undergone malignant peripheral nerve sheath tumour transformation on histology. He was a poor surgical risk for tumour debulking procedure. In view of the available literature and role of c-kit signalling in neurofibromatosis, he was treated with Imitinib. Four months after the treatment his Cushings had resolved on biochemical testing. After a year his plexiform neurofibroma has not increased in size. To our knowledge, this is the first case of NF1 associated with clinical and biochemical features of Cushing's secondary to ectopic ACTH due to MPNST in a plexiform neurofibroma and its resolution on treatment with imatinib

    Isospin non-equilibrium in heavy-ion collisions at intermediate energies

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    We study the equilibration of isospin degree of freedom in intermediate energy heavy-ion collisions using an isospin-dependent BUU model. It is found that there exists a transition from the isospin equilibration at low energies to non-equilibration at high energies as the beam energy varies across the Fermi energy in central, asymmetric heavy-ion collisions. At beam energies around 55 MeV/nucleon, the composite system in thermal equilibrium but isospin non-equilibrium breaks up into two primary hot residues with N/Z ratios closely related to those of the target and projectile respectively. The decay of these forward-backward moving residues results in the strong isospin asymmetry in space and the dependence of the isotopic composition of fragments on the N/Z ratios of the target and projectile. These features are in good agreement with those found recently in experiments at NSCL/MSU and TAMU, implications of these findings are discussed.Comment: 9 pages, latex, + 3 figures available upon reques

    5 year Global 3-mm VLBI survey of Gamma-ray active blazars

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    The Global mm-VLBI Array (GMVA) is a network of 14 3\,mm and 7\,mm capable telescopes spanning Europe and the United States, with planned extensions to Asia. The array is capable of sensitive maps with angular resolution often exceeding 50\,ÎŒ\muas. Using the GMVA, a large sample of prominent Îł\gamma-ray blazars have been observed approximately 6 monthly from later 2008 until now. Combining 3\,mm maps from the GMVA with near-in-time 7\,mm maps from the VLBA-BU-BLAZAR program and 2\,cm maps from the MOJAVE program, we determine the sub-pc morphology and high frequency spectral structure of Îł\gamma-ray blazars. The magnetic field strength can be estimated at different locations along the jet under the assumption of equipartition between magnetic field and relativistic particle energies. Making assumptions on the jet magnetic field configuration (e.g. poloidal or toroidal), we can estimate the separation of the mm-wave "core" and the jet base, and estimate the strength of the magnetic field there. The results of this analysis show that on average, the magnetic field strength decreases with a power-law B∝r−nB \propto r^{-n}, n=0.3±0.2n=0.3 \pm 0.2. This suggests that on average, the mm-wave "core" is ∌1−3\sim 1-3\,pc downstream of the de-projected jet apex and that the magnetic field strength is of the order Bapex∌5−20B_{\rm{apex}} \sim 5-20\,kG, broadly consistent with the predictions of magnetic jet launching (e.g. via magnetically arrested disks (MAD)).Comment: 6 pages, 1 figur

    Collisions of particles in locally AdS spacetimes II Moduli of globally hyperbolic spaces

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    We investigate 3-dimensional globally hyperbolic AdS manifolds containing "particles", i.e., cone singularities of angles less than 2π2\pi along a time-like graph Γ\Gamma. To each such space we associate a graph and a finite family of pairs of hyperbolic surfaces with cone singularities. We show that this data is sufficient to recover the space locally (i.e., in the neighborhood of a fixed metric). This is a partial extension of a result of Mess for non-singular globally hyperbolic AdS manifolds.Comment: 29 pages, 3 figures. v2: 41 pages, improved exposition. To appear, Comm. Math. Phys. arXiv admin note: text overlap with arXiv:0905.182
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