The black silicon method II: the effect of mask material and loading on the reactive ion etching of deep silicon trenches

Very deep trenches in Si with smooth controllable profiles are etched using a fluorine-based Reactive Ion Etcher(RIE). The effect of various mask materials and loading on the profile is examined using the Black Silicon Method. It is found that most metal layers have an almost infinite selectivity. When the aspect ratio of the trenches is beyond five, RIE lag is found to be an important effect. Evidence is found that this effect is caused by the bowing of incoming ions by the electrical field

Constructing irreducible representations of discrete groups

The decomposition of unitary representations of a discrete group obtained by induction from a subgroup involves commensurators. In particular Mackey has shown that quasi-regular representations are irreducible if and only if the corresponding subgroups are self-commensurizing. The purpose of this work is to describe general constructions of pairs of groups Γ0 with Γ its own commensurator in Γ. These constructions are then applied to groups of isometries of hyperbolic spaces and to lattices in algebraic group

Infinite dimensional non-positively curved symmetric spaces of finite rank

This paper concerns a study of three families of non-compact type symmetric spaces of infinite dimension. Although they have infinite dimension they have finite rank. More precisely, we show they have finite telescopic dimension. We also show the existence of Furstenberg maps for some group actions on these spaces. Such maps appear as a first step toward superrigidity results.Comment: Some references have been adde

Equivalence of pathologists' and rule-based parser's annotations of Dutch pathology reports

Introduction: In the Netherlands, pathology reports are annotated using a nationwide pathology network (PALGA) thesaurus. Annotations must address topography, procedure, and diagnosis. The Pathology Report Annotation Module (PRAM) can be used to annotate the report conclusion with PALGA-compliant code series. The equivalence of these generated annotations to manual annotations is unknown. We assess the equivalence of annotations by authoring pathologists, pathologists participating in this study, and PRAM. Methods: New annotations were created for one thousand histopathology reports by the PRAM and a pathologist panel. We calculated dissimilarity of annotations using a semantic distance measure, Minimal Transition Cost (MTC). In absence of a gold standard, we compared dissimilarity scores having one common annotator. The resulting comparisons yielded a measure for the coding dissimilarity between PRAM, the pathologist panel and the authoring pathologist. To compare the comprehensiveness of the coding methods, we assessed number and length of the annotations. Results: Eight of the twelve comparisons of dissimilarity scores were significantly equivalent. Non-equivalent score pairs involved dissimilarity between the code series by the original pathologist and the panel pathologists. Coding dissimilarity was lowest for procedures, highest for diagnoses: MTC overall = 0.30, topographies = 0.22, procedures = 0.13, diagnoses = 0.33. Both number and length of annotations per report increased with report conclusion length, mostly in PRAM-annotated conclusions: conclusion length ranging from 2 to 373 words, number of annotations ranged from 1 to 10 for pathologists, 1–19 for PRAM, annotation length ranged from 3 to 43 codes for pathologists, 4–123 for PRAM. Conclusions: We measured annotation similarity among PRAM, authoring pathologists and panel pathologists. Annotating by PRAM, the panel pathologists and to a lesser extent by the authoring pathologist was equivalent. Therefore, the use of annotations by PRAM in a practical setting is justified. PRAM annotations are equivalent to study-setting annotations, and more comprehensive than routine coding. Further research on annotation quality is needed

Isometry groups of non-positively curved spaces: structure theory

We develop the structure theory of full isometry groups of locally compact non-positively curved metric spaces. Amongst the discussed themes are de Rham decompositions, normal subgroup structure and characterising properties of symmetric spaces and Bruhat--Tits buildings. Applications to discrete groups and further developments on non-positively curved lattices are exposed in a companion paper: "Isometry groups of non-positively curved spaces: discrete subgroups".Comment: The original version (September 2, 2008) has been split into two articles. This is the first part; the second is available as of today on the arxiv under the title: "Isometry groups of non-positively curved spaces: discrete subgroups

Mutual Event Observations of Io's Sodium Corona

We have measured the column density profile of Io's sodium corona using 10 mutual eclipses between the Galilean satellites. This approach circumvents the problem of spatially resolving Io's corona directly from Io's bright continuum in the presence of atmospheric seeing and telescopic scattering. The primary goal is to investigate the spatial and temporal variations of Io's corona. Spectra from the Keck Observatory and McDonald Observatory from 1997 reveal a corona that is only approximately spherically symmetric around Io. Comparing the globally averaged radial sodium column density profile in the corona with profiles measured in 1991 and 1985, we find that there has been no significant variation. However, there appears to be a previously undetected asymmetry: the corona above Io's sub-Jupiter hemisphere is consistently more dense than above the anti-Jupiter hemisphere

Understanding the Telematic Apparatus

Under the conditions of its geographic distribution, the “telematic performance” can be regarded as a remediation of traditional concert, theater or dance formats. Conversely, and as this paper argues, the telematic performance can also be understood as an artistic format of its own right, one which then can serve as a trope for social interaction under the conditions of critical posthumanism. To gain a wider perspective, this paper analyzes Alan Turing’s “Imitation Game” from his seminal article Computing Machinery and Intelligence, 1950, proposing it as an early conceptualization of a telematic performance. This against-the-grain reading of Turing’s text reveals certain attributes that are distinctive to this type of performance. Following a descriptive and analytic critique of the “Turing Test,” Vilém Flusser’s theoretical considerations of digitization and technical apparatuses comes into play. In the second and main part of the paper, these findings are applied to a series of artistic practices with telematic performances developed by a research team at Zurich University of the Arts. The section details the construction of telematic apparatuses and demonstrates the multilayered interaction between human and nonhuman agents