Metric completion versus ideal completion

Complete partial orders have been used for a long time for defining semantics of programming languages. In the context of concurrency de Bakker and Zucker (1982) proposed a metric setting for handling concurrency, recursion and nontermination, which has proved to be very successful in many applications. Starting with a semantic domain D for ‘finite behaviour’ we investigate the relation between the ideal completion Idl(D) and the metric completion which are both suitable to model recursion and infinite behaviour. We also consider the properties of semantic operators.     

Zero forcing and minimum mean-square-error equalization formultiuser detection in code-division multiple-access channels

In code-division multiple-access (CDMA) systems transmitting over time-varying multipath channels, both intersymbol interference (ISI) and multiple-access interference (MAI) arise. The conventional suboptimum receiver consisting of a bank of matched filters is often inefficient because interference is treated as noise. The optimum multiuser detector is too complex to be implemented at present. Four suboptimum detection techniques based on zero forcing (ZF) and minimum mean-square-error (MMSE) equalization with and without decision feedback (DF) are presented and compared. They combat both ISI and MAI. The computational complexity of all four equalizers is essentially the same. All four equalizers are independent of the size of the data symbol alphabet. It is shown that the performance of the MMSE equalizers is better than that of the corresponding ZF equalizers. Furthermore, the performance of the equalizers with DF is better than that of the corresponding equalizers without DF. The impairing effect of error propagation on the equalizers with DF is reduced by channel sorting     

Radiation intensity from ultrarelativistic particles during axial channeling and its orientation dependence

The radiation intensity I of ultrarelativistic electrons and positrons during axial channeling in thin crystals is calculated using a realistic model for the axial potential. The approach used avoids a cumbersome analysis of radiation from concrete trajectories. A general expression for the intensity I(?_o) as a function of the incident angle ?_o of the particles, which is valid for any ax potential U(ρ), is derived. Explicit formulas for the potential [eq. (29)] are given. Intensities I(?_o) for axial and planar chann compared.     

Control of Acanthoscelides obtectus Say (Coleoptera: Bruchidae) in Phaseolus vulgaris L. Seed stored on small farms—II. Germination and cooking time

Treatments which successfully controlled bruchids in on-farm experiments were evaluated to determine effects on seed quality and cooking time. Relative cooling time was determined by cooking beans to the half-cooked point in a modified Mattson cooker. Germination was determined by trials planted in sand, and seedling vigor was estimated by dry weight of 8-day old seedlings. Cooking time, germination, and seedling vigor were not significantly changed by storage treatment with vegetable oil, threshing residues, kitchen ash, Malathion and black pepper. Analysis of bruchid damage on seed quality showed a decline in germination and seedling vigor related to the number of emergence holes.     

Role of lipids in development of noninsulin-dependent diabetes mellitus: Lessons learned from pima indians

We studied the role of lipids in the pathogenesis of nonlinsulin-dependent diabetes mellitus (NIDDM) in Pima Indians. High plasma levels of nonesterified fatty acid (NEFA) predicted development of NIDDM, but this effect cannot entirely be explained by the glucose-fatty acid cycle. Dyslipidemia, although often associated with diabetes, did not seem to predict NIDDM, and might rather be associated with or the consequence of insulin resistance. In some individuals, a single amino acid substitution in the intestinal fatty acid binding protein could result, in increased rates of intestinal absorption of dietary NEFA and thereby contribute to increased lipid-oxidation rates and insulin resistance.     

Normal Computation for Discrete Surfaces in 3D Space

Associating normal vectors to surfaces is essential for many rendering algorithms. We introduce a new method to compute normals on discrete surfaces in object space. Assuming that the surface separates space locally into two disjoint subsets, each of these subsets contains implicitly information about the surface inclination. Considering one of these subsets in a small neighbourhood of a surface point enables us to derive the surface normal from this set. We show that this leads to exact results for C¹ continuous surfaces in R³. Furthermore, we show that good approximations can be obtained numerically by sampling the considered area. Finally, we derive a method for normal computation on surfaces in discrete space.     

Tissue-on-Tissue Testing of Dry Eye Formulations for Reduction of Bioadhesion

Glutaraldehyde-preserved, human umbilical cord vein graft (UCVG) was selected as a stable surrogate tissue source for testing of bioadhesion-reducing lubricants. Bioadhesion, as manifested in tissue-on-tissue friction coefficients of 0.2-0.4 for saline-lubricated UCVG, was quantitatively and persistently reduced after the instillation of a single aliquot of an ophthalmic “artificial tears” formulation containing active demulcents polyethylene glycol (PEG400) and propylene glycol (PG), as well as a gellable hydroxypropyl guar (HP Guar) in a borate-buffered solution between the “blinking” tissues. Reduced adhesion was maintained (was “substantive”), even after rinsing excess lubricant from the surfaces. Comparative tests with tissue-on-solid, and solid-on-solid, similarly lubricated couples point to a potentially unique mechanism that involves macromolecules modifying the tissue phases to provide rinse-resistant lubricity and surface protection in articulated tissue-to-tissue interfaces. Results for tissue-on-tissue couples were obtained in laboratory trials utilizing a reciprocating pin-on-disc type friction/wear test device articulating preserved human umbilical cord vein segments under increasing loads, and again after saline rinsing to determine persistence of the friction-reducing effects. A single confirmatory test using donated human cornea against vein graft tissue showed the lowest coefficient of friction, below 0.05, for the “artificial tears” formulation. Mechanistic studies employing the same test device and protocol for metal oxide (germanium)-on-metal oxide couples, as well as for metal oxide-on-tissue couples, indicated that simple increases in viscosity were not the likely sources of friction reduction, and revealed frictional values higher than measured for the similarly lubricated tissue-on-tissue couples. Thus, formulation development to minimize bioadhesion requires that appropriate simulations be used to obtain clinically predictive data for circumstances of liquid uptake into the tissues, resultant tissue swelling, and binding to impermeable adjacent materials.