Encoding textual criticism

This paper chronicles the work of the TEI textual criticism working groups through several phases, documenting how and why the design goals were shaped by the requirements of several distinct user communities and by the nature of the textual evidence itself. Encoding schemes for the representation of physical details of textual witnesses were unified with encoding schemes for critical editing practices when it was observed that the two phenomena were inextricably layered and linked within real texts. Rationale is offered for the development teams' adherence to exceedingly general design principles: (a) the requirement that the encoding notations be neutral in text-theoretic terms; (b) the need to accommodate dramatically different text-transmission phenomena and research goals within diverse text-critical arenas; (c) the need for commensurability of the text-critical markup with encoding notations used in closely related text-analytic research. The paper also assesses the results of the effort in terms of the encoding scheme's adequacy for several scholarly purposes: suggestions are made concerning the need for programmatic testing, for refinement, and for extension of the encoding model to support a broader range of text-transmission phenomena and research objectives.     

1.4-/spl mu/m InGaAsP-InP strained multiple-quantum-well laser for broad-wavelength tunability

InGaAsP-InP strained multiple-quantum-well (MQW) lasers for extended wavelength tunability in external cavity operation were designed, fabricated, and tested. The active layer was a strain compensated structure consisting of three 3.2/spl plusmn/0.3 nm and three 6.4/spl plusmn/0.3 nm 1.0% compressive strained wells and five 10.3/spl plusmn/0.3 nm 0.45% tensile strained barrier layers. A 2-/spl mu/m-wide ridge waveguide laser of length 250 /spl mu/m, when used in a grating external cavity and with no coatings to alter the reflectivity of the facets, was observed to operate over a range >110 nm. The lasers were designed for applications in trace gas and liquid detection with the goal to maximize the tunable range when operated in external cavities and with no facet coatings.     

A comparison of different models for assessing variations in the sero-prevalence of infectious bovine rhinotracheitis by farm, area and district in Kenya

The relative variability of the sero-prevalence of antibodies to infectious bovine rhinotracheitis (IBR) due to cow, farm, and agroecological area levels were investigated for three contrasting districts in Kenya: Samburu, an arid and pastoral area; Kiambu, a tropical highland area; and Kilifi, a typical tropical coastal area. Cattle were selected by two-stage cluster sampling and visited once between August 1991 and 1992. Data on animal, farm, and area factors were analyzed using Schall's algorithm and MLn (multi-level, n-level), two generalized mixed-model programs suitable for multi-level analysis. Most variation in IBR sero-prevalence was from farm-to-farm. This was reflected by the many farm-level fixed effects (farm size, disease control measures and type of breeding) significant in models both ignoring and accounting for single variance components (clustering) at farm, area, and district levels. Area-to-area and district-to-district variations were noted but the area and district variance components were one-third and one-fifth the size of the farm variance components for both methods. As farm-to-farm variation differed markedly by farm size and district, models in MLn were extended to allow for multiple farm-level variance components by these categories. For each, sero-prevalence of IBR increased with age and was significantly decreased on small-sized zero-grazing farms. These models, particularly the model with different farm variance components by districts, fit the data better and highlighted well that there was considerable farm-to-farm variation--differing by district--and that the available farm-level fixed effects did not predict IBR sero-prevalence well.     

Comparative effects of enteric-coated pancreatin microsphere therapy after conventional and pylorus-preserving pancreatoduodenectomy

BACKGROUND: A comparative study was performed between patients with exocrine pancreatic insufficiency after conventional pancreatoduodenectomy (Whipple's procedure) and pylorus-preserving pancreatoduodenectomy (PPPD). In these patients the pharmacodynamics of 2-mm enteric-coated pancreatin microspheres (ECPMs) and their gastric transit time in relation to that of a solid meal were investigated. The efficacy of ECPM preparations may differ after Whipple's procedure compared with PPPD, because the latter procedure does not include gastrectomy. METHODS: Gastric transit was assessed by double-isotope scintigraphy. A pancake meal was labelled with 99mTc. ECPMs were cold-labelled with 170Er and neutron activated shortly before ingestion to enable imaging with a gamma camera. Intraluminal pancreatic enzyme activity was assessed during a 6-h period with two indirect tests: the cholesteryl [14C]octanoate breath test and the N-benzoyl-L-tyrosyl-p-aminobenzoic acid-p-aminosalicylic acid (NBT-PABA-PAS) test. RESULTS: In patients who had Whipple's procedure, the gastric transit time of ECPMs and of the pancake meal was not significantly different. The outcome of the indirect pancreatic function tests during enzyme supplementation was comparable, and not significantly different, from that in healthy volunteers. In patients who had PPPD, however, the gastric transit time of microspheres was greatly delayed compared with that of the pancake meal (P < 0.05). Improvement in the outcome of the indirect pancreatic function tests during enzyme supplementation was much less and remained well below that of healthy volunteers (P < 0.05). CONCLUSION: In cases of exocrine pancreatic insufficiency after Whipple's procedure, 2-mm ECPM treatment adequately restores pancreatic enzyme activity. Following PPPD, however, ECPM treatment is often ineffective because the microspheres are retained in the stomach. In these patients, use of conventional powdered pancreatin enzyme preparations may improve the efficacy of treatment.     

Angle diversity and space diversity experiments on theSalton/Brawley hop

Space diversity and angle diversity experimental data have been collected over a three year period, using 64 quadrature amplitude modulation (QAM) radios, on the terrestrial microwave radio hop between Salton and Brawley in southern California. Both measured data and simulations have shown that the performance of angle diversity systems depends on the direction of transmission as well as the polarization of the signal. While this may also be true for space diversity, the effects of a finite spatial correlation length and a small signal-to-noise ratio significantly reduce the sensitivity of space diversity to the direction of propagation. Additionally, the performance of angle diversity is shown to depend upon the method used to implement angle diversity     

Diffusion of hydrogen in titanium alloys due to composition,temperature, and stress gradients

A theoretical and experimental study was conducted to determine the combined effects on interstitial diffusion in metals of gradients in interstitial concentration, in solvent composition, in stress, and in temperature. The theory consolidates relationships, some of which have been previously published. It is based on macroscopic irreversible thermodynamics, and is applicable to anisotropic or Isotropic materials. Experiments were conducted and literature analyzed to determine the numerical quantities required to predict the change in hydrogen distribution with time for pure and alloy titanium, where the solvent gradient, stress gradient, and temperature gradient are constant with time. The diffusion driving forces for solute gradient, solvent gradient, and stress gradient are related to the effect of each factor on hydrogen activity. In addition, the material property which determines the diffusion driving force of a stress gradient for anisotropic material is a matter tensor analogous to the scalar partial molal volume used for isotropic material. The experiments, conducted with commercially pure titanium and titanium alloy, 6A1-4V, consist of measuring the effect of alloy additions and stress on the hydrogen activity in solid solution and the dilatation effect of hydrogen. Stress states tested were tension, compression, and torsion. The measurements were made by exposing titanium and the alloy to hydrogen at temperatures from 600° to 800° C, and measuring the equilibrium hydrogen gas pressure at various solid solution hydrogen contents. Both materials were tested with and without stress. Tension decreased the activity, compression increased it, and torsion had no effect. This is consistent with the stress effect theory of Li, Oriani, and Darken. The stress effect corresponds to an apparent partial molal volume of 1.7 to 2.2 cm³/mol, depending on the alloy and hydrogen content.