Fixed point iteration on pointsymmetric interference graphs

Interference graphs are used for performance analysis of multiprocessor interconnection networks. In order to model blocked transmissions, nodes can have three states: idle, active or blocked. The resulting steady state probability distribution has a non-product form. Macro states are introduced to calculate performance measures, and the corresponding macro state probability distribution is approximated by a special type of fixed point iteration: the macro approximation, which is very efficient for pointsymmetric interference graphs

Shark and ray teeth from the Hauterivian (Lower Cretaceous) of north-east England

Sampling of hiatal horizons within the Hauterivian part of the Speeton Clay Formation of north-east England has produced teeth of several species of sharks and rays, four of which are previously unnamed. One species of shark, Cretorectolobus doylei sp. nov., and two species of rays, Spathobatis rugosus sp. nov. and Dasyatis speetonensis sp. nov., are named, whilst the presence of an indeterminate triakid shark is also noted. Synechodus dubrisiensis (Mackie) is shown to be a senior synonym of S. michaeli Thies. Although the dasyatid ray and triakid shark are by far the oldest representatives of their respective families, the overall composition of the fauna is considered to resemble more closely assemblages known from the Jurassic than those from upper parts of the Cretaceous

Microborings in mid Cretaceous fish teeth

Fish teeth and other remains from the British Cretaceous contain abundant evidence for post-mortem colonization by endolithic organisms. The borings are here recognised as occurring in three morphotypes, including a flask-shaped form not previously recorded. There is strong evidence to suggest that each of these boring types shows a strong preference for a particular substrate histology. The damage and destruction of vertebrate remains by microborings is here considered to exert a major taphonomic control on microvertebrate assemblages. The relationships between the intensity of colonization of vertebrate material by endolithic organisms and palaeoenvironment have implications for using these bone microborings as palaeoenvironmental indicators

CPAC optical moisture monitoring: Characterization of composition and physical effects on moisture determination Task 2A report

The impact of particle size and chemical composition variations on determination of tank simulant moisture from near infrared (NIR) optical spectra are presented. This work shows particle size and chemical variations will impact moisture predictions from NIR spectra. However, the prediction errors can be minimized if calibration models are built with samples containing these variations as interferents. Prior work showed the NIR spectral region (1100 to 2500 nm) could be used to predict moisture content of BY-104 tank simulant with a standard error less of approximately 0.5 wt%. Particle size will increase moisture prediction error if calibration-models do not include the same particle size ranges as unknown samples. A combined particle size model with 0-420 {times}10{sup -6}m, 420-841 {times} 10{sup -6}m, and 841 {times} 10{sup -6} m-2 mm diameter particles predicted 0.59, 0.34 nd 0.23 wt% errors respectively for samples containing only these size ranges and 0.80 wt% error for a samples with all particle size ranges. Chemical composition would also increase moisture prediction error if calibration model samples chemically differ from unknown samples. For a BY-104 simulant, increases in NaOH, NaAlO{sub 2}, Na{sub 2} SiO{sub 3}, and Na{sub 3}PO{sub 4} produced moisture predictions that were lower than the actual moisture levels while increases in FE(NO{sub 3}){sub 3}, Ca(NO{sub 3}){sub 2}, and Mg (NO{sub 3}){sub 2} resulted in a higher than actual moisture prediction. Systematic changes in the NIR spectra could be observed for these families of materials. When all of the composition variations were included in a single model, the model had a moisture prediction error of 1.41 wt% as compared to a 2.96 wt% error without model changes. This work shows a calibration model based on a single set of tightly controlled experimental conditions will tend to have somewhat larger prediction errors when applied to samples collected with variations outside of such conditions

On the unavoidability of metastable behaviour. (Computing science notes

Abstract The unavoidability of metastable behaviour in digital circuit-components like flipflops, arbiters and synchronisers is based on the assumption that the point representing such systems in phase space follows a trajectory which depends continuously on initial conditions. The validity of this assumption is well-established for existing implementations, and claimed for all implementations that are possible according to the classical laws of physics. In this paper we argue that the validity of the continuity assumption for quantum mechanical systems is an open question

Recovery of intracranial stenoses in varicella zoster virus vasculitis after long-term treatment with valacyclovir and prednisolone

BACKGROUND AND PURPOSE: Optimal treatment of intracranial stenoses in varicella zoster virus (VZV)-associated vasculitis is unknown. This study aims to evaluate the merits and potential pitfalls of a specific therapeutic strategy, initially proposed by Don Gilden in 2015. METHODS: We describe three patients with intracranial stenoses caused by VZV vasculitis successfully treated by a long-term combination of valacyclovir and prednisolone. RESULTS: All three patients were young men suffering from stroke. Only one reported a first contact to VZV in adulthood. All three presented stenoses in the intracranial part of the internal carotid artery or the proximal segments of the middle cerebral artery as well as an elevated cell count and positive VZV antibody index in cerebrospinal fluid. They received a combination therapy regimen with prednisone and valacyclovir about a minimum of one year. Intracranial stenoses improved markedly in one and almost resolved completely in the other two patients. Side effects of corticosteroid treatment occurred in two patients. CONCLUSIONS: Long-term combination treatment with prednisone and valacyclovir proved to be effective in three young men suffering from intracranial stenosis due to VZV vasculitis

An interface to retrieve personal memories using an iconic visual language

Relevant past events can be remembered when visualizing related pictures. The main difficulty is how to find these photos in a large personal collection. Query definition and image annotation are key issues to overcome this problem. The former is relevant due to the diversity of the clues provided by our memory when recovering a past moment and the later because images need to be annotated with information regarding those clues to be retrieved. Consequently, tools to recover past memories should deal carefully with these two tasks. This paper describes a user interface designed to explore pictures from personal memories. Users can query the media collection in several ways and for this reason an iconic visual language to define queries is proposed. Automatic and semi-automatic annotation is also performed using the image content and the audio information obtained when users show their images to others. The paper also presents the user interface evaluation based on tests with 58 participants