Hotmap: looking at geographic attention

Understanding how people use online maps allows data acquisition teams to concentrate their efforts on the portions of the map that are most seen by users. Online maps represent vast databases, and so it is insufficient to simply look at a list of the most-accessed URLs. Hotmap takes advantage of the design of a mapping system's imagery pyramid to superpose a heatmap of the log files over the original maps. Users' behavior within the system can be observed and interpreted. This paper discusses the imagery acquisition task that motivated Hotmap, and presents several examples of information that Hotmap makes visible. We discuss the design choices behind Hotmap, including logarithmic color schemes; low-saturation background images; and tuning images to explore both infrequently-viewed and frequently-viewed spaces.     

The role of the surface amorphous layer of articular cartilage in joint lubrication

Articular cartilage is a complex soft tissue that performs multiple functions in the joint. In particular, the amorphous layer that covers the surface of articular cartilage is thought to play some role in lubrication. This study aimed to characterize the surface amorphous layer (SAL) using a variety of techniques, including environmental scanning electron microscopy, transmission electron microscopy, white light interferometry, and biochemical analysis of its composition. Friction tests were conducted to investigate the role of the SAL in lubrication. A protocol to remove successfully the SAL without damaging the underlying cartilage was developed and the material removed from healthy cartilage was found to contain approximately equal quantities of glycosaminoglycan (GAG), protein, and lipid. Cartilage-on-cartilage friction tests were conducted on fresh, healthy cartilage with and without the SAL, under both dynamic and static operating conditions. Removal of the SAL was not found to change the friction coefficient. However, subsequent staining of specimens indicated that the SAL had replenished during the test following loading. The replenished SAL was characterized and found to contain lipids and sulphated GAGs with undetectable protein. This study revealed experimental evidence of surface layer replenishment in articular cartilage. It was postulated that the surface layer regeneration mechanism was purely mechanical and associated with movement of GAGs and lipids through the cartilage matrix during deformation, since the experimental set-up did not contain any means of biochemical activation.     

Healthcare data warehousing and quality assurance

Healthcare data warehousing presents unique challenges. The industry is rife with often incompatible medical standards and coding schemes that require careful translation. Healthcare data comes from many sources and is delivered in many forms, including published books, individual spreadsheets, and several tape or data formats. Results derived from a healthcare data warehouse must be delivered in accessible form to diverse stakeholders, including healthcare regulators, physicians, hospital administrators, consumers, community activists, and members of the popular press. The industry's widely decentralized and largely autonomous data collection efforts make data quality a significant challenge. Finally, the sensitivity of healthcare data makes privacy and security issues paramount. Healthcare data warehousing will make rigorous, quantitative information available to healthcare decision makers. The authors describe a fully functional healthcare data warehouse used to produce several reports for communities throughout Florida. Building on this work, they're actively pursuing a research agenda to enhance technical data warehousing capabilities while investigating innovative community and clinical healthcare applications     

Model checking agent programming languages

In this paper we describe a verification system for multi-agent programs. This is the first comprehensive approach to the verification of programs developed using programming languages based on the BDI (belief-desire-intention) model of agency. In particular, we have developed a specific layer of abstraction, sitting between the underlying verification system and the agent programming language, that maps the semantics of agent programs into the relevant model-checking framework. Crucially, this abstraction layer is both flexible and extensible; not only can a variety of different agent programming languages be implemented and verified, but even heterogeneous multi-agent programs can be captured semantically. In addition to describing this layer, and the semantic mapping inherent within it, we describe how the underlying model-checker is driven and how agent properties are checked. We also present several examples showing how the system can be used. As this is the first system of its kind, it is relatively slow, so we also indicate further work that needs to be tackled to improve performance.     

Transmission microscopy of the corrosion scale formed on a stainless steel exposed to liquid sodium

The scale, formed on 304 stainless steel during exposure to sodium for 85 days, was removed electrolytically, examined in transmission in the Hitachi high voltage microscope and found to consist of hexagonal close packed crystallites, typically 0.3 to 1 m in diameter. Approximately 90% of the crystallites were of basal (0001) orientation and the others either of {4, ¯1, ¯3, 15} or {¯2110} orientations. Lattice parametersa=2.96 Å andc=13.89 Å were determined by analysing electron diffraction patterns derived from the scale. Confirmatory evidence was obtained by examining the scale formed after a shorter exposure of 29 days, in the Philips EM 200 microscope. Previous studies [1, 2] have indicated that the scale may be sodium chromite (with lattice parametersa=2.96 Å andc=15.95 Å). The results of the present study are in apparent conflict with this suggestion unless a contraction parallel to thec-axis 13% is assumed.     

Haemoglobins of the shark, Heterodontus portusjacksoni II. Amino acid sequence of the alpha-chain

The amino acid sequence of the alpha-chain of the principal haemoglobin from the shark, H. portusjacksoni has been determined. The chain has 148 residues and is acetylated at the amino terminal. The soluble peptides obtained by tryptic and chymotryptic digestion of the protein or its cyanogen bromide fragments were isolated by gel filtration, paper ionophoresis and paper chromatography. The amino acid sequences were determined by the dansyl-Edman procedure. The insoluble "core" peptide from the tryptic digestion contained 34 residues and required cleavage by several prosteases before the sequence was established. Compared with human alpha-chain there are 88 amino acid differences including the additional seven residues which appear on the amino terminal of the shark chain. There is also one deletion and one insertion. The chain contains no tryptophan but has four cysteinyl residues which is the highest number of such residues recorded for a vertebrate globin. In the alpha1beta1 contact sites there are four changes in the oxyhaemoglobin form and six deoxy form. Nine of the 16, alpha1beta1 contact sites show variation while three of the haem contact sites have changed in comparison to the residues known to be involved in these interactions in horse haemoglobin alpha-chain. Use of the sequence data to estimate a time of divergence of the shark from the main vertebrate line yielded the value of 410 +/- 46 million years. The data, in general, support the palaeontological view that bony fishes arose before the elasmobranchs.     

Effect of prolactin suppression on gonadotrophic secretion in the puerperium

Serum levels of prolactin (PRL), FSH, LH and oestradiol-17 beta were determined by radioimmunoassay in 57 lactating women and in 20 women in whom lactation was inhibited by ergocryptine (CS-154). Women who breast fed their infants exhibited high PRL levels which abruptly declined within 48 h post-partum, and remained low for the duration of the study. Serum FSH was undetectable during the first week post-partum in lactating as well as in CB-154 treated women. Thereafter, lactating women showed increasing FSH levels which reached a maximum by the third week post-partum. These FSH values were higher in lactating women than in the CBS-154 treated group. In contrast, LH levels were higher in those women receiving CB-154. Serum oestradiol-17 beta remained in low levels throughout the study, and no difference was observed between the two groups of subjects. From these results it seems that: 1) inhibition of PRL secretion leads to a faster recovery of gonadotrophin secretion toward the "menstrual type", and 2) PRL suppression produces no effect on the ovarian oestrogen production.     

Turbulence generated by vibrating wire resonators in superfluid 4He at low temperatures

No Heading We have measured responses of vibrating wire resonators in superfluid ⁴He at millikelvin temperatures. We find evidence for turbulence generation above a critical velocity on the order of a few cm/s. At the critical velocity for the onset of turbulence, the resonator velocity abruptly decreases and shows hysteretic behavior. Surprisingly we find that the resonant frequencies of the resonators increase in the turbulent regime. We also find that the critical velocity may be reduced by the presence of turbulence generated by a neighboring vibrating wire resonator, allowing the detection of existing turbulence in the low temperature regime.PACS numbers: 67.40 Vs, 67.40 Pm     

Model checking rational agents

Agent-oriented programming techniques seem appropriate for developing systems that operate in complex, dynamic, and unpredictable environments. We aim to address this requirement by developing model-checking techniques for the (automatic or semiautomatic) verification of rational-agent systems written in a logic-based agent-oriented programming language. Typically, developers apply model-checking techniques to abstract models of a system rather than the system implementation. Although this is important for detecting design errors at an early stage, developers might still introduce errors during coding. In contrast, developers can directly apply our model-checking techniques to systems implemented in an agent-oriented programming language, automatically verifying agent systems without the usual gap between design and implementation. We developed our techniques for AgentSpeak, a rational-agent programming language based on the AgentSpeak (L) abstract agent-oriented programming language. AgentSpeak shares many features of the agent-oriented programming paradigm. Similarly, we've developed techniques for automatically translating AgentSpeak programs into the model specification language of existing model-checking systems. In this way, we reduce the problem of verifying that an AgentSpeak system has certain BDI logic properties to a conventional LTL model-checking problem.     

Design of a reconfigurable planar parallel manipulator

This work presents the design of a reconfigurable planar parallel manipulator (RPPM). The RPPM is designed to act as a testbed manipulator for theories on redundant actuation of parallel manipulators and can reconfigure into three different revolute-jointed mechanism types: a 2-branch 2-DOF (degree-of-freedom) 5-bar mechanism; a 2-branch 3-DOF 6-bar mechanism; and a 3-branch 3-DOF 8-bar mechanism. The design of the RPPM allows for any shoulder or elbow joint to be actuated. In this work, the criteria and constraints of the design are presented. The final design of the RPPM is shown, followed by a discussion of the final design and how it relates to the initial design criteria and constraints. © 2004 Wiley Periodicals, Inc.