864 research outputs found

    Trigeminal neuralgia

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    AbstractTwo different clinical entities, essential or secondary neuralgia, are associated with different pathologies. The pathways of CN V comprise the cervical spine, the brainstem, the root of the nerve and the three peripheral branches: V1, V2 and V3. The lesions responsible for neuralgia are neoplastic, vascular, inflammatory, malformative or post-traumatic. The examination protocol should explore the set of CN V pathways. Neurovascular compression is the main cause of essential neuralgia. It is investigated by T2-weighted inframillimetric volume. Two conditions are necessary to diagnose a neurovascular compression: localised on the root entry zone [(REZ), 2–6mm from the emergence of the pons] and perpendicularly. In the absence of neurovascular compression, thin slices and a gadolinium injection are necessary

    Imaging sub-milliarcsecond stellar features with intensity interferometry using air Cherenkov telescope arrays

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    Recent proposals have been advanced to apply imaging air Cherenkov telescope arrays to stellar intensity interferometry (SII). Of particular interest is the possibility of model-independent image recovery afforded by the good (u, v)-plane coverage of these arrays, as well as recent developments in phase retrieval techniques. The capabilities of these instruments used as SII receivers have already been explored for simple stellar objects, and here the focus is on reconstructing stellar images with non-uniform radiance distributions. We find that hot stars (T > 6000 K) containing hot and/or cool localized regions (T \sim 500 K) as small as \sim 0.1 mas can be imaged at short wavelengths ({\lambda} = 400 nm).Comment: Accepted for publication in MNRAS. 6 pages, 10 figure

    Imaging the spotty surface of Betelgeuse in the H band

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    This paper reports on H-band interferometric observations of Betelgeuse made at the three-telescope interferometer IOTA. We image Betelgeuse and its asymmetries to understand the spatial variation of the photosphere, including its diameter, limb darkening, effective temperature, surrounding brightness, and bright (or dark) star spots. We used different theoretical simulations of the photosphere and dusty environment to model the visibility data. We made images with parametric modeling and two image reconstruction algorithms: MIRA and WISARD. We measure an average limb-darkened diameter of 44.28 +/- 0.15 mas with linear and quadratic models and a Rosseland diameter of 45.03 +/- 0.12 mas with a MARCS model. These measurements lead us to derive an updated effective temperature of 3600 +/- 66 K. We detect a fully-resolved environment to which the silicate dust shell is likely to contribute. By using two imaging reconstruction algorithms, we unveiled two bright spots on the surface of Betelgeuse. One spot has a diameter of about 11 mas and accounts for about 8.5% of the total flux. The second one is unresolved (diameter < 9 mas) with 4.5% of the total flux. Resolved images of Betelgeuse in the H band are asymmetric at the level of a few percent. The MOLsphere is not detected in this wavelength range. The amount of measured limb-darkening is in good agreement with model predictions. The two spots imaged at the surface of the star are potential signatures of convective cells.Comment: 10 pages, 10 figures, accepted for publication in A&A, references adde

    Visual processing speed is linked to functional connectivity between right frontoparietal and visual networks

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    Visual information processing requires an efficient visual attention system. The neural theory of visual attention (TVA) proposes that visual processing speed depends on the coordinated activity between frontoparietal and occipital brain areas. Previous research has shown that the coordinated activity between (i.e., functional connectivity and “inter-FC”) cingulo-opercular (COn) and right-frontoparietal (RFPn) networks is linked to visual processing speed. However, how inter-FC of COn and RFPn with visual networks links to visual processing speed has not been directly addressed yet. Forty-eight healthy adult participants (27 females) underwent resting-state (rs-)fMRI and performed a whole-report psychophysical task. To obtain inter-FC, we analyzed the entire frequency range available in our rs-fMRI data (i.e., 0.01–0.4 Hz) to avoid discarding neural information. Following previous approaches, we analyzed the data across frequency bins (Hz): Slow-5 (0.01–0.027), Slow-4 (0.027–0.073), Slow-3 (0.073–0.198), and Slow-2 (0.198–0.4). We used the mathematical TVA framework to estimate an individual, latent-level visual processing speed parameter. We found that visual processing speed was negatively associated with inter-FC between RFPn and visual networks in Slow-5 and Slow-2, with no corresponding significant association for inter-FC between COn and visual networks. These results provide the first empirical evidence that links inter-FC between RFPn and visual networks with the visual processing speed parameter. These findings suggest that direct connectivity between occipital and right frontoparietal, but not frontoinsular, regions support visual processing speed

    Model Kebijakan Penanggulangan Korupsi di Universitas Negeri YOGYAKARTA

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    Penelitian ini bertujuan untuk mengetahui kebijakan Universitas Negeri Yogyakarta dalam menanggulangi korupsi dan menemukan model kebijakan yang diinginkan Universitas Negeri Yogyakarta dalam menanggulangi korupsi. Penelitian ini adalah penelitian survei dengan pendekatan kuantitatif dan kualitatif. Sampel penelitian ditentukan secara multy stage sampling dengan teknik pengumpulan data dengan angket, dokumen dan diperkuat dengan pengumpulan data melalui Focus Group Discussion (FGD), dan validasi instrumen melalui validitas isi (content validity). Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa kebijakan penanggulangan korupsi di UNY tidak ada secara khusus dikeluarkan. Kebijakan yang ada mengikuti dan mempertahankan kebijakan yang lebih tinggi, yaitu dari Pemerintah. Model kebijakan penangggulangan korupsi di UNY yang digunakan adalah Model Rasional, yaitu kebijakan penanggulangan korupsi yang dikeluarkan merupakan aspirasi semua staf yang ada di unit kerja dan harus menekankan pada aspek efisiensi atas beban kerja pada unit kerja yang bersangkutan. Adapun kebijakan yang sudah ada yang berasal dari Pemerintah pusat dijadikan pedoman

    VSI: the VLTI spectro-imager

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    The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions down to 1.1 milliarcsecond and spectral resolutions up to R=12000. Targets as faint as K=13 will be imaged without requiring a brighter nearby reference object. The unique combination of high-dynamic-range imaging at high angular resolution and high spectral resolution enables a scientific program which serves a broad user community and at the same time provides the opportunity for breakthroughs in many areas of astrophysic including: probing the initial conditions for planet formation in the AU-scale environments of young stars; imaging convective cells and other phenomena on the surfaces of stars; mapping the chemical and physical environments of evolved stars, stellar remnants, and stellar winds; and disentangling the central regions of active galactic nuclei and supermassive black holes. VSI will provide these new capabilities using technologies which have been extensively tested in the past and VSI requires little in terms of new infrastructure on the VLTI. At the same time, VSI will be able to make maximum use of new infrastructure as it becomes available; for example, by combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through the measurement of up to 28 visibilities in every wavelength channel within a few minutes. The current studies are focused on a 4-telescope version with an upgrade to a 6-telescope one. The instrument contains its own fringe tracker and tip-tilt control in order to reduce the constraints on the VLTI infrastructure and maximize the scientific return.Comment: 12 pages, to be published in Proc. SPIE conference 7013 "Optical and Infrared Interferometry", Schoeller, Danchi, and Delplancke, F. (eds.). See also http://vsi.obs.ujf-grenoble.f

    The Schroš\ddot{o}dinger-Poisson equations as the large-N limit of the Newtonian N-body system: applications to the large scale dark matter dynamics

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    In this paper it is argued how the dynamics of the classical Newtonian N-body system can be described in terms of the Schroš\ddot{o}dinger-Poisson equations in the large NN limit. This result is based on the stochastic quantization introduced by Nelson, and on the Calogero conjecture. According to the Calogero conjecture, the emerging effective Planck constant is computed in terms of the parameters of the N-body system as ℏ∌M5/3G1/2(N/)1/6\hbar \sim M^{5/3} G^{1/2} (N/)^{1/6}, where is GG the gravitational constant, NN and MM are the number and the mass of the bodies, and is their average density. The relevance of this result in the context of large scale structure formation is discussed. In particular, this finding gives a further argument in support of the validity of the Schroš\ddot{o}dinger method as numerical double of the N-body simulations of dark matter dynamics at large cosmological scales.Comment: Accepted for publication in the Euro. Phys. J.
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