Practice guideline for examination of the placenta: developed by the Placental Pathology Practice Guideline Development Task Force of the College of American Pathologists

The Placental Pathology Practice Guideline Development Task Force, a multidisciplinary group, has prepared this guideline to assist those involved with placental examination. It provides recommendations related to indications and methods for placental examination as well as sample worksheets. An algorithm for the handling of placentas summarizes the recommendations of the guideline. A summary of specific findings of placental examination together with their pathogenesis and clinical associations is also provided. Recommendations related to reporting with sample reporting formats are included. The guideline is intended as an educational tool, and its use should be guided by the individual circumstances and care setting of specific cases.     

Automatic tumor segmentation using knowledge-based techniques

A system that automatically segments and labels glioblastoma-multiforme tumors in magnetic resonance images (MRI's) of the human brain is presented. The MRI's consist of T1-weighted, proton density, and T2-weighted feature images and are processed by a system which integrates knowledge-based (KB) techniques with multispectral analysis. Initial segmentation is performed by an unsupervised clustering algorithm. The segmented image, along with cluster centers for each class are provided to a rule-based expert system which extracts the intracranial region. Multispectral histogram analysis separates suspected tumor from the rest of the intracranial region, with region analysis used in performing the final tumor labeling. This system has been trained on three volume data sets and tested on thirteen unseen volume data sets acquired from a single MRI system. The KB tumor segmentation was compared with supervised, radiologist-labeled "ground truth" tumor volumes and supervised k-nearest neighbors tumor segmentations. The results of this system generally correspond well to ground truth, both on a per slice basis and more importantly in tracking total tumor volume during treatment over time.     

Neural network modelling for environmental prediction

We describe the choice and assessment of neural network and statistical methods for data modelling, feature selection and forecasting. We deal in particular with how empirical environmental and Earth observation data can be used in conjunction with physical simulation models.     

Configuring the Mobile User: Sociological and Industry Views

This article considers the role of the consumer in the diffusion of mobile telecommunications technologies. There is presently little research on the consumption and use of mobile technologies, and the aim of the present paper is to facilitate discussion about the way consumer behaviour is currently understood in industry and academia. The paper considers key themes in social science research on mobile ICTs, and understandings of the consumer held by those in the mobile industry. Bringing these understandings together, we reiterate the now well attested view that the diffusion and consumption of mobile telephony and computing cannot be understood without investigating the contexts and processes of their use in everyday life.     

Annealing study of InGaP/GaAs heterojunction bipolar transistor and carbon-doped pGaAs base layers

In this work we have examined the effect of RF annealing (450–750°C, 5–30 min) upon both InGaP/GaAs-based hetero-junction bipolar transistor (HBT) structures, fabricated by metalorganic vapour phase epitaxy (MOVPE), as well as thick carbon (C)-doped p⁺GaAs HBT base layers with varying layer thickness, dopant level and type (intrinsic and extrinsic C precursors) and co-doping (In) strain compensation. Anneal-induced changes in the p⁺GaAs layer lattice strain, Hall carrier concentration and mobility were compared with non-radiative losses, determined from photoluminescence (PL) intensity data. Majority and minority carrier property differences were also compared with IR reflection, Raman backscattering and photoreflectance (PR) data and correlated with changes in MOVPE hydrogen background concentration as determined by secondary-ion-mass-spectroscopy (SIMS). Thick base layer (1.3 μm) HBT structures were also examined for different anneal temperatures and time, showing significant changes in the PR emitter(InGaP)/base (p⁺GaAs) and base/collector (n-GaAs) interface regions for the 650°C anneal condition, as correlated with both PL and SIMS hydrogen concentration data.     

Multiband segmentation based on a hierarchical Markov model

We develop a new multiscale Markov segmentation model for multiband images. Using quadtree multiple resolution analysis of a multiband image, we use both inter- and intra-scale spatial Markov statistical dependencies. Bayesian inference is used to assess the appropriate number of segments. We exemplify the excellent results which can be obtained with this approach using synthetic images, and in two case studies involving multiband astronomical image sets.     

Comments on `Parallel algorithms for hierarchical clustering andcluster validity'

In the above-titled paper (ibid., vol.12, no.11, p.1088-92, Nov. 1990), parallel implementations of hierarchical clustering algorithms that achieve O(n²) computational time complexity and thereby improve on the baseline of sequential implementations are described. The latter are stated to be O( n³), with the exception of the single-link method. The commenter points out that state-of-the-art hierarchical clustering algorithms have O(n²) time complexity and should be referred to in preference to the O(n³ ) algorithms, which were described in many texts in the 1970s. Some further references in the parallelizing of hierarchic clustering algorithms are provided     

Redundant proofs of non-interference in Levin-Gries CSP program proofs

Summary The proof system for Hoare's CSP language proposed by Levin and Gries requires that non-interference be proven for each assertion used in the proof of a process. In the worst case, the effort required to provide such proofs could be enormous. The need for these proofs has been identified as a significant weakness of the system. In this paper, we show that most of the proofs of non-interference required are unnecessary. This suggest that proving non-interference in the Levin-Gries system may be far less burdensome than had previously been assumed.