POEMS: program for outliers elimination in multidimensional space

A Program for Outliers Elimination in Multidimensional Space (POEMS), which allows the user to eliminate outliers from training spaces as a prior step to any statistical study, is presented. Even though the program can be applied to any scientific field, the characteristics of POEMS makes it particularly suitable for 'series design' on Quantitative Structure-Activity Relationships studies.     

The Macintosh Programmer's Workshop

The authors discuss the Macintosh Programmer's Workshop (MPW), a Macintosh development environment that includes a comprehensive set of programming tools and handles several languages. It also combines the graphical interface common to all Macintosh applications, a command language similar to the Unix shell languages, and Smalltalk's immediate execution of commands in any window. They focus on the program-development environment rather than on the tools in that environment. They give the history of MPW, and describe its design goals. The bulk of the article is a discussion of MPW's design     

Liquid–liquid extraction of a recombinant protein with reverse micelles

Recombinant cytochrome b₅ was extracted into the reversed micelle phase of an anionic surfactant (AOT) in octane and back-extracted to a final aqueous phase. The extraction of the protein was controlled by an electrostatic mechanism, since it was dependent on the global charge of the protein. This was directly demonstrated by experiments with native and mutant cytochromes obtained by site directed mutagenesis. The back-extraction of cytochrome b₅ to a fresh aqueous phase was decreased by factors that reduced the size of the water pool of the organic phase, such as high salt concentrations (1–2 mol dm^?3 NaCl) and low temperatures (4°C), probably because of an increase in a favourable interaction of this protein with the surfactant at closer distances.     

A simplified method for calculating the substation grounding gridresistance

A simple and accurate formula for calculating the grounding grid resistance is proposed in this paper. This method is based on a theoretical manipulation of the numerical moment method and of the current image. The formula is dependent on the substation grounding grid design, such as grid depth, grid size, number of meshes, grid-conductor diameter, etc. A comparison study is performed to check the accuracy of the proposed formula with respect to six different formulas and methods in the literature. An excellent agreement was found between the results of this formula and the results of a sophisticated computerized method     

Influence of surface treatment on the photoelectrochemical behaviour of Y-Ba-Cu-O thin films

Y-Ba-Cu-O films with different surface treatments have been studied by photoelectrochemical and XPS measurements. The influence of etching by bromine in ethanol of these films has been followed by means of the electrochemical oxidation of ferrocene in an aprotic electrolyte. From the dependence of dark and photocurrent on etching time it is concluded that Y-Ba-Cu-O thin films on LaAlO₃ are covered by a 1, 1nm thick nonstoichiometric surface layer. The cathodic polarization of Y-Ba-Cu-O at -0,9 V vs. Ag/AgCl in acetonitrile/0,1 M lithium perchlorate leads to the formation of a lithium-containing, oxygen-enriched surface layer. The photoelectrochemical response of the reduced films is similar to that of cuprous oxide and passive layers on copper.     

Performance and the i860 microprocessor

The internal design of the i860 CPU, which exploits pipelining and parallelism more than previous microprocessors, is described. The i860 uses RISC concepts and memory-performance optimizations in several novel ways. Other innovations include simultaneous floating-point operations similar to digital signal processing, a two-instruction-per-clock mode, fast floating-point pipelines graphics instructions, and high-bandwidth registers and caches on-chip. These features make it one of the fastest single-chip processors available     

Study of the polymerization of Mo(VI) in weakly acidic concentrated (10−2M) paramolybdate solutions using the Mo/Fe atomic ratio of the equilibrium iron molybdate precipitates

The polymerization of Mo(VI) is investigated using the Mo/Fe atomic ratio of the equilibrium precipitates of iron molybdates obtained with a small Fe(III) excess. The overall formation equation of isopolymolybdate ions is deduced which presents the state of molybdate ions as a function of pH and concentration of the Mo(VI) solution.     

Optical fiber up-tapers with index perturbations-performanceanalysis

The performance of step index up-tapers subjected to certain index perturbations in investigated by computer simulation. Concentric symmetric and asymmetric index profile perturbations as well as localized spherical, called regions bubbles, having a different index are studied. It is found that some low-valued perturbations of small scale size (less than a wavelength) do not alter the optical fiber performance. However, the amount of beam expansion in the up-taper may be ultimately limited by such perturbations. Excessive magnification in the presence of perturbations can cause a distortion of the quasi-Gaussian shape and symmetry of the pure step-index fundamental mode as well as increase the excess loss and degrade the lateral and axial displacement tolerance improvements of the up-tapers. For example, an index variation of Δn≈10^-5 in conjunction with a perturbation scale size of 40 μm can be detrimental. Bubble-type perturbations could also cause similar problems. A single 12.8-μm-diameter bubble with a relative index of -0.02, embedded in a 128-μm-diameter step index core with relative index of 0.5%, produced a 0.3-dB excess loss     

High-speed picosecond optical pulse compression from gain-switched 1.3-µm distributed feedback-laser diode (DFB-LD) through highly dispersive single-mode fiber

Picosecond optical pulse compression characteristics of chirped pulses from gain-switched distributed feedback-laser diodes (DFB-LD) transmitting through highly dispersive media are studied theoretically and experimentally. It is clarified theoretically that gain-switched chirped pulses can be compressed to about a 0.7-time bandwidth product by normal dispersion of the dispersive media and that the optimum dispersion value to obtain a minimum compressed pulse is proportional to the square of original pulsewidth. Through a dispersion, shifted single-mode fiber with -48-ps/nm normal dispersion at a 1.3-μm wavelength, gain-switched 30-ps (FWHM) pulses from a directly modulated 1.3-μm DFB-LD at a 4.4-GHz repetition rate have been successfully compressed to 6.4-ps optical pulses with a 0.86-time bandwidth product. Experimental results agree with the theoretical analysis.     

Survival of Yersinia enterocolitica and Escherichia coli in spring water

Survival of pure and mixed cultures of Yersinia enterocolitica and Escherichia coli in sterile spring water stored at 4 degrees C was evaluated. Y. enterocolitica increased two or three logs during the first 3 weeks of incubation, and at the end of 64 weeks viable cells in numbers corresponding to the initial inoculum level were still detectable. However, after 1 week of incubation, the number of E. coli in water started to decrease and in 13 weeks time no E. coli was detected. More rapid decrease of E. coli was observed in mixed cultures.