437 research outputs found

    A study of high power argon laser optics Final report, 15 Apr. 1967 - 14 Apr. 1968

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    Window degradation in high power argon laser optic

    A study of high power argon laser optics Interim scientific report, 15 Apr. - 31 Oct. 1967

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    Argon laser optimal component degredation at high power level

    AML-MO: Clinical entity or waste basket for immature blastic leukemias? A description of 14 patients

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    In the period from August 1991 to August 1994, the Dutch Slide Review Committee of Adult Leukemias classified 14 leukemias as AML-M0. We reviewed the clinical characteristics and response to therapy of these patients. Eight patients were male. Patients' age ranged from 7 to 77 years (medium age 62 years). There was a striking homogeneity in morphological appearance of the blasts, being small to medium-sized round cells with often an eccentric nucleus with fine chromatin, several distinct nucleoli, and a high nucleo-cytoplasmic ratio. In addition to myeloid-associated markers such as CD13 and CD33, the blasts of all patients were positive for CD34 and HLA-DR, pointing to their immature differentiation stage. TdT was present in the blasts of 71%, CD7 was positive in the blasts of 42% of the patients. No consistent cytogenetic abnormalities were found. With respect to the treatment outcome, four patients achieved a complete remission after remission-induction treatment. The median survival was 4.5 months. Our present study shows AML-M0 to be an immature leukemia, uniform in morphology and immunological phenotype, with no consistent cytogenetic phenotype and with a poor clinical outcome

    Exact Piecewise Flat Gravitational Waves

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    We generalize our previous linear result [1] in obtaining gravitational waves from our piecewise flat model for gravity in 3+1 dimensions to exact piecewise flat configurations describing exact planar gravitational waves. We show explicitly how to construct a piecewise flat spacetime that describes an impulsive plane wavefront. From these wavefronts more general plane waves may be constructed

    FMRI resting slow fluctuations correlate with the activity of fast cortico-cortical physiological connections

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    Recording of slow spontaneous fluctuations at rest using functional magnetic resonance imaging (fMRI) allows distinct long-range cortical networks to be identified. The neuronal basis of connectivity as assessed by resting-state fMRI still needs to be fully clarified, considering that these signals are an indirect measure of neuronal activity, reflecting slow local variations in de-oxyhaemoglobin concentration. Here, we combined fMRI with multifocal transcranial magnetic stimulation (TMS), a technique that allows the investigation of the causal neurophysiological interactions occurring in specific cortico-cortical connections. We investigated whether the physiological properties of parieto-frontal circuits mapped with short-latency multifocal TMS at rest may have some relationship with the resting-state fMRI measures of specific resting-state functional networks (RSNs). Results showed that the activity of fast cortico-cortical physiological interactions occurring in the millisecond range correlated selectively with the coupling of fMRI slow oscillations within the same cortical areas that form part of the dorsal attention network, i.e., the attention system believed to be involved in reorientation of attention. We conclude that resting-state fMRI ongoing slow fluctuations likely reflect the interaction of underlying physiological cortico-cortical connections

    Cosmological Black Holes

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    In this paper we propose a model for the formation of the cosmological voids. We show that cosmological voids can form directly after the collapse of extremely large wavelength perturbations into low-density black holes or cosmological black holes (CBH). Consequently the voids are formed by the comoving expansion of the matter that surrounds the collapsed perturbation. It follows that the universe evolves, in first approximation, according to the Einstein-Straus cosmological model. We discuss finally the possibility to detect the presence of these black holes through their weak and strong lensing effects and their influence on the cosmic background radiation.Comment: 14 pages, new completely revised version, to appear on GR
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