Parametrization of reflectometry fluctuation frequency spectra for systematic study of fusion plasma turbulence.

We describe a way to parameterize power spectra extracted from fixed-frequency reflectometry data, with a view to systematic studies of turbulence properties in tokamak plasmas. Analysis of typical frequency spectra obtained from a new database suggests decomposition in a set of four key components: the direct current component, low-frequency fluctuations, broadband (BB) turbulence, and the noise level. For the decomposition in the identified components, different kinds of functions are tested and their fitting performance is analyzed to determine the optimal spectrum parametrization. In particular, for the BB turbulence, three models are compared qualitatively based on a number of representative spectrum test cases, notably the generalized Gaussian, the Voigt, and the Taylor model. In addition, quantitative performance testing is accomplished using the weighted residual sum of squares and the Bayesian information criterion in a large database including 350 000 spectra obtained in Tore Supra. Next, parametrization by the Taylor model is applied to Ohmically heated plasmas, and a BB energy basin is systematically observed in the core plasma region, which shrinks with decreasing radial position of the q = 1 surface. This basin might be explained by a drop of the density fluctuation level inside the q = 1 surface.

Robust analysis of trends in noisy tokamak confinement data using geodesic least squares regression.

Regression analysis is a very common activity in fusion science for unveiling trends and parametric dependencies, but it can be a difficult matter. We have recently developed the method of geodesic least squares (GLS) regression that is able to handle errors in all variables, is robust against data outliers and uncertainty in the regression model, and can be used with arbitrary distribution models and regression functions. We here report on first results of application of GLS to estimation of the multi-machine scaling law for the energy confinement time in tokamaks, demonstrating improved consistency of the GLS results compared to standard least squares.

A classification scheme for edge-localized modes based on their probability distributions.

We present here an automated classification scheme which is particularly well suited to scenarios where the parameters have significant uncertainties or are stochastic quantities. To this end, the parameters are modeled with probability distributions in a metric space and classification is conducted using the notion of nearest neighbors. The presented framework is then applied to the classification of type I and type III edge-localized modes (ELMs) from a set of carbon-wall plasmas at JET. This provides a fast, standardized classification of ELM types which is expected to significantly reduce the effort of ELM experts in identifying ELM types. Further, the classification scheme is general and can be applied to various other plasma phenomena as well.

Finding the elusive E×B staircase in magnetized plasmas.

Turbulence in hot magnetized plasmas is shown to generate permeable localized transport barriers that globally organize into the so-called "ExB staircase" [G. Dif-Pradalier et al., Phys. Rev. E, 82, 025401(R) (2010)]. Its domain of existence and dependence with key plasma parameters is discussed theoretically. Based on these predictions, staircases are observed experimentally in the Tore Supra tokamak by means of high-resolution fast-sweeping X-mode reflectometry. This observation strongly emphasizes the critical role of mesoscale self-organization in plasma turbulence and may have far-reaching consequences for turbulent transport models and their validation.

[The hypoglossal channel and its contents in the posterolateral access to the petroclival area]. / Uber den Canalis hypoglossi und seinen Inhalt beim postero-lateralen Zugang zur petroclivalen Region.

Measurements of the hypoglossal canal: The midpoint of the inner orifice of the hypoglossal canal is on average somewhat over 26 mm away from the opisthion. The distances of the canal centre come to approximately 30 mm, those of the outer canal orifice to 34 mm. The distance of the intracranial pores from each other amounts to 28 xmm. The medial portal for the extracranial pore is on an average 33 mm away from the portal of the opposite side, the lateral 40 mm from the lateral portal of the opposite side. The intracranial pore of the canal for the XII. nerve is situated on an average 13 mm in front of the posterior rim of the occipital condyle, the midpoint of the canal is 15.85 mm in front of this measuring zone, and the exit of the canal 19 mm. Some differences between the sexes and measurements of the postnatal increase of these distances have been included in this investigation. The diagnostic and surgical importance of the hypoglossal canal are discussed.

[Progressive multifocal leukoencephalopathy. Late complication in chronic lymphatic leukemia]. / Progressive multifokale Leukoenzephalopathie. Spätkomplikation bei chronischer lymphatischer Leukämie.

In a 44 year old patient with chronic lymphatic leukemia and secondary antibody deficiency syndrome, a disorder of articulation and a left hemiparesis developed during a thrombocytopenic phase. Computer tomography of the cranium, CSF diagnostics and the electroencephalogram did not provide any indication for the cause of the rapidly progressive cerebral symptoms. In the NMR tomogram, a diffusedly increasing intensity in the T2-weighted tomograms were shown around the central region in the right brain. The patient died of a Pseudomonas septicemia. At autopsy, a typical finding of progressive multifocal leukoencephalopathy was found in the areas altered in the NMR tomography. Papova-like virions could be demonstrated in glial cells by electron microscopy.

Corticosteroid-induced changes in glucose metabolism of chondrocytes.

Immature mice were treated for up to 12 weeks with daily doses of triamcinolone diacetate. Using quantitative histochemical methods, the proximal epiphyseal plate of the humerus was studied at regular intervals. By the tenth injection significant decrease was noted in the acid glycosaminoglycans content (25%) and in the neutral mucopolysaccharides (30%). Concomitantly, a marked increase was noted in the intracellular depots of glycogen (70%). It is suggested that the hormone's antiglycolytic effect in cartilage caused the glucose metabolic pathway to divert in the direction of glycogen synthesis, and thereby interfered with the normal synthetic pathway of the chondrocytes. The hormone's primary effect on the cells' hexose metabolism could be responsible, at least in part, for its inhibitory influence on bone growth.