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- Ciavola, G., et al.
(författare)
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Status report of the multipurpose superconducting electron cyclotron resonance ion source
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:2, s. 02A326-
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Tidskriftsartikel (refereegranskat)abstract
- Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 1013 cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.
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- Testa, D., et al.
(författare)
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LTCC magnetic sensors at EPFL and TCV: Lessons learnt for ITER
- 2019
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Ingår i: Fusion Engineering and Design. - : Elsevier BV. - 0920-3796. ; 146, s. 1553-1558
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Tidskriftsartikel (refereegranskat)abstract
- Innovative 3D high-frequency magnetic sensors have been designed and manufactured in-house for installation on the Tokamak a Configuration Variable (TCV), and are currently routinely operational. These sensors combine the Low Temperature Co-fired Ceramic (LTCC) and the thick-film technologies, and are in various aspects similar to the majority of the inductive magnetic sensors currently being procured for ITER (290 out of 505 are LTCC-1D). The TCV LTCC-3D magnetic sensors provide measurements in the frequency range up to 1MHz of the perturbations to the toroidal (quasi-parallel: delta B-TOR(similar to)delta B-PAR), vertical (quasi-poloidal: delta B-V(ER)similar to delta B-PO(L)), and radial (delta B-RAD) magnetic field components, the latter being generally different from the component normal to the Last Closed Flux-Surface (delta B-NOR). The LTCC-3D delta B-RAD measurements improve significantly on the corresponding data with the saddle loops, which are mounted onto the wall and have a bandwidth of (similar to)3 kHz (due to the wall penetration time). The LTCC-3D delta B-TOR measurements (not previously available in TCV) provide evidence that certain MHD modes have a finite delta B-P(AR) at the LCFS, as recently calculated for pressure-driven instabilities. The LTCC-3D delta B-PO(L) measurements allow to cross-check the data obtained with the Mirnov coils, and led to the identification of large EM noise pick-up for the Mirnov DAQ. The LTCC-3D data for delta B-POL agree with those obtained with the Mirnov sensors in the frequency range where the respective data acquisition overlap, routinely up to 125kHz, and up to 250kHz in some discharges, when the EM noise pick-up on the Mirnov DAQ is removed. Finally, we look at what lessons can be learnt from our work for the forthcoming procurement, installation and operation of the LTCC-1D sensors in ITER.
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- Maillard, A M, et al.
(författare)
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The 16p11.2 locus modulates brain structures common to autism, schizophrenia and obesity.
- 2015
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Ingår i: Molecular psychiatry. - : Springer Science and Business Media LLC. - 1476-5578 .- 1359-4184. ; 20:1, s. 140-7
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Tidskriftsartikel (refereegranskat)abstract
- Anatomical structures and mechanisms linking genes to neuropsychiatric disorders are not deciphered. Reciprocal copy number variants at the 16p11.2 BP4-BP5 locus offer a unique opportunity to study the intermediate phenotypes in carriers at high risk for autism spectrum disorder (ASD) or schizophrenia (SZ). We investigated the variation in brain anatomy in 16p11.2 deletion and duplication carriers. Beyond gene dosage effects on global brain metrics, we show that the number of genomic copies negatively correlated to the gray matter volume and white matter tissue properties in cortico-subcortical regions implicated in reward, language and social cognition. Despite the near absence of ASD or SZ diagnoses in our 16p11.2 cohort, the pattern of brain anatomy changes in carriers spatially overlaps with the well-established structural abnormalities in ASD and SZ. Using measures of peripheral mRNA levels, we confirm our genomic copy number findings. This combined molecular, neuroimaging and clinical approach, applied to larger datasets, will help interpret the relative contributions of genes to neuropsychiatric conditions by measuring their effect on local brain anatomy.
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- Dravins, Dainis, et al.
(författare)
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Absolute wavelength shifts - A new diagnostic for rapidly rotating stars
- 2004
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Ingår i: Stellar Rotation; IAU Symposium. - 0074-1809. ; :215, s. 27-32
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Konferensbidrag (refereegranskat)abstract
- Accuracies reached in space astrometry now permit. the accurate determination of astrometric radial velocities. without any use of spectroscopy. Knowing this true stellar motion, spectral shifts; intrinsic to stellar atmospheres can be identified, for instance gravitational redshifts and those caused by, velocity fields on stellar surfaces. The astrometric accuracy is independent. of any spectral complexity, such as the smeared-out line profiles of rapidly rotating stars. Besides a better determination of stellar velocities, this permits more precise studies of atmospheric dynamics, such as possible modifications of stellar surface convection (granulation) by rotation-induced forces, as well as a potential for observing meridional flows across stellar surfaces.
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- Maeder, Philippe P, et al.
(författare)
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Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis
- 1990
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Ingår i: AJNR. - 1936-959X. ; 155:1, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- Eight patients with colloid cysts of the third ventricle were examined with CT and MR. In six, surgical resection was performed and the material was subjected to histologic evaluation; the concentrations of trace elements were determined by particle-induced X-ray emission. Stereotaxic aspiration was performed in two. The investigation showed that colloid cysts are often iso- or hypodense relative to brain on CT (5/8), but sometimes have a center of increased density. Increased density did not correlate with increased concentration of calcium or other metals but did not correlate with high cholesterol content. Colloid cysts appear more heterogeneous on MR (6/8) than on CT (3/8), despite a homogeneous appearance at histology. High signal on short TR/TE sequences is correlated with a high cholesterol content. A marked shortening of the T2 relaxation time is often noticed in the central part of the cyst. Analysis of trace elements showed that this phenomenon is not related to the presence of metals with paramagnetic effects. Our analysis of the contents of colloid cysts does not support the theory that differing metallic concentrations are responsible for differences in MR signal intensity or CT density. We did find that increased CT density and high MR signal correlated with high cholesterol content.
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