5,118 research outputs found
Primary radiotherapy in progressive optic nerve sheath meningiomas: a long-term follow-up study
Background/aims: To report the outcome of primary radiotherapy in patients with progressive optic nerve sheath meningioma (ONSM). Methods: The clinical records of all patients were reviewed in a retrospective, observational, multicentre study. Results: Thirty-four consecutive patients were included. Twenty-six women and eight men received conventional or stereotactic fractionated radiotherapy, and were followed for a median 58 (range 51–156) months. Fourteen eyes (41%) showed improved visual acuity of at least two lines on the Snellen chart. In 17 (50%) eyes, the vision stabilised, while deterioration was noted in three eyes (9%). The visual outcome was not associated with age at the time of radiotherapy (p=0.83), sex (p=0.43), visual acuity at the time of presentation (p=0.22) or type of radiotherapy (p=0.35). Optic disc swelling was associated with improved visual acuity (p<0.01) and 4/11 patients with optic atrophy also showed improvement. Long-term complications were dry eyes in five patients, cataracts in three, and mild radiation retinopathy in four. Conclusion: Primary radiotherapy for patients with ONSM is associated with long-term improvement of visual acuity and few adverse effects.Peerooz Saeed, Leo Blank, Dinesh Selva, John G. Wolbers, Peter J.C.M. Nowak, Ronald B. Geskus, Ezekiel Weis, Maarten P. Mourits, Jack Rootma
Automated assembly of large double-sided microstrip detector modules of the CBM Silicon Tracking System at FAIR
The detector modules of the Silicon Tracking System of the Compressed Baryonic Matter experiment at FAIR comprise double-sided silicon microstrip sensors with a size of up to 124 mm x 62 mm. Due to tight material budget constraints, the sensors are connected to the read-out electronics by long flexible microcables. As manual assembly of the modules is time-consuming and difficult, a fully customized in-house bonder machine has been developed which allows for a highly automated detector module assembly. We present the requirements and the setup of the bonder machine together with the achieved alignment accuracy and first assemblies
Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films
Detailed analysis of transport, magnetism and x-ray absorption spectroscopy
measurements on ultrathin La0.7Sr0.3MnO3 films with thicknesses from 3 to 70
unit cells resulted in the identification of a lower critical thickness for a
non-metallic, non-ferromagnetic layer at the interface with the SrTiO3 (001)
substrate of only 3 unit cells (~12 Angstrom). Furthermore, linear dichroism
measurements demonstrate the presence of a preferred (x2-y2) in-plane orbital
ordering for all layer thicknesses without any orbital reconstruction at the
interface. A crucial requirement for the accurate study of these ultrathin
films is a controlled growth process, offering the coexistence of
layer-by-layer growth and bulk-like magnetic/transport properties.Comment: 22 pages, 6 figures, accepted for publication in Physical Review
Chaotic Cascades with Kolmogorov 1941 Scaling
We define a (chaotic) deterministic variant of random multiplicative cascade
models of turbulence. It preserves the hierarchical tree structure, thanks to
the addition of infinitesimal noise. The zero-noise limit can be handled by
Perron-Frobenius theory, just as the zero-diffusivity limit for the fast dynamo
problem. Random multiplicative models do not possess Kolmogorov 1941 (K41)
scaling because of a large-deviations effect. Our numerical studies indicate
that deterministic multiplicative models can be chaotic and still have exact
K41 scaling. A mechanism is suggested for avoiding large deviations, which is
present in maps with a neutrally unstable fixed point.Comment: 14 pages, plain LaTex, 6 figures available upon request as hard copy
(no local report #
On the discovery of doubly-magic Ni
The paper reports on the first observation of doubly-magic Nickel-48 in an
experimental at the SISSI/LISE3 facility of GANIL. Four Nickel-48 isotopes were
identified. In addition, roughly 100 Nickel-49, 50 Iron-45, and 290 Chromium-42
isotopes were observed. This opens the possibility to search for two-proton
emission from these nuclei.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let
The non-self-adjointness of the radial momentum operator in n dimensions
The non self-adjointness of the radial momentum operator has been noted
before by several authors, but the various proofs are incorrect. We give a
rigorous proof that the -dimensional radial momentum operator is not self-
adjoint and has no self-adjoint extensions. The main idea of the proof is to
show that this operator is unitarily equivalent to the momentum operator on
which is not self-adjoint and has no self-adjoint
extensions.Comment: Some text and a reference adde
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