Combination calculi for uncertainty reasoning: representing uncertainty using distributions

There are many different methods for incorporating notions of uncertainty in evidential reasoning. A common component to these methods is the use of additional values, other than conditional probabilities, to assert current degrees of belief and certainties in propositions. Beginning with the viewpoint that these values can be associated with statistics of multiple opinions in an evidential reasoning system, we categorize the choices that are available in updating and tracking these multiple opinions. In this way, we develop a matrix of different uncertainty calculi, some of which are standard, and others are new. The main contribution is to formalize a framework under which different methods for reasoning with uncertainty can be evaluated. As examples, we see that both the “Kalman filtering” approach and the “Dempster–Shafer” approach to reasoning with uncertainty can be interpreted within this framework of representing uncertainty by the statistics of multiple opinions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Polarization control in a vertical cavity surface emitting laser submitted to optical feedback

We study experimentally and theoretically two polarization effects in a vertical cavity surface emitting laser submitted to optical feedback. In a first experiment, we obtain flips between two linearly polarized laser modes up to a frequency of 50 MHz using an external cavity with a polarizer. In a second experiment, polarization self modulation is demonstrated up to a frequency of 2.6 GHz, using a quarter wave plate instead. Numerical calculations, based on a four levels model for the active medium, show a good agreement with the experiments.     

Solution structure of a DNA duplex containing the exocyclic lesion 3,N4-etheno-2'-deoxycytidine opposite 2'-deoxyguanosine

Vinyl chloride reacts with cellular DNA producing 3,N4-etheno-2'-deoxycytidine (epsilonC) along with other exocyclic adducts. The solution structure of an oligodeoxynucleotide duplex containing an epsilonC.dG base pair was determined by high-resolution NMR spectroscopy and molecular dynamics simulations. NMR data indicated that the duplex adopts a right-handed helical structure having all residues in anti orientation around the glycosylic torsion angle. The epsilonC adduct has a sugar pucker in the C3'-endo/C4'-exo region while the rest of the residues are in the C2'-endo/C3'-exo range. NOE interactions established Watson-Crick alignments for canonical base pairs of the duplex. The imino proton of the lesion-containing base pair resonated as a sharp signal that was resistant to water exchange, suggesting hydrogen bonding. Restrained molecular dynamics simulations generated three-dimensional models in excellent agreement with the spectroscopic data. The refined structures are slightly bent at the lesion site without major perturbations of the sugar-phosphate backbone. The adduct is displaced and shifted toward the major groove of the helix while its partner on the complementary strand remains stacked. The epsilonC(anti).dG(anti) base pair alignment is sheared and stabilized by the formation of hydrogen bonds. The biological implications of structures of epsilonC-containing DNA duplexes are discussed.     

Micropipelined asynchronous discrete cosine transform (DCT/IDCT)processor

We describe the design and implementation of an asynchronous discrete cosine transform/inverse discrete cosine transform (DCT/IDCT) processor core compliant with the CCITT recommendation H.261. First, a micropipelined implementation with level-sensitive latches is shown. This is improved by replacing the level-sensitive latches with dual-edge triggered flip-flops to save power and using completion-detection adders in the critical stage of the pipeline to exploit the data-dependent processing delay. Gate-level simulation of extracted layouts indicates that the performance of asynchronous implementations is comparable with that of a synchronous implementation based on an identical architecture. This is because part of the penalty introduced by handshaking circuitry in an asynchronous pipeline can be recovered by exploiting data-dependent processing delays with completion-detection circuitry. In pipelines with significant arithmetic processing such as the DCT/IDCT processor, this is easily accomplished. Our results are encouraging because asynchronous designs do not employ global clocking. In the near future when clock generation, clock distribution, and the power consumed in the clock circuitry become limiting factors in the design of large synchronous application specific integrated circuits (ASICs), asynchronous implementation methodology could be pursued as a real alternative     

Identification of the DRB1*1313 allele in a sibling pair

Amines such as dopamine, norepinephrine and epinephrine were analysed in the brain regions of O.mossambicus exposed to quinalphos, phenthoate and their combination for 96 hr. The three types of treatments significantly (P < 0.05) altered the amines level at various intervals in the brain regions.     

Mechanomyography and oxygen consumption during incremental cycle ergometry

Brucella abortus strain RB51 was recently approved as an official brucellosis calfhood vaccine for cattle by the Animal and Plant Health Inspection Service branch of the United States Department of Agriculture. Currently available serologic surveillance tests for B. abortus do not detect seroconversion following SRB51 vaccination. The purpose of this study was to evaluate a dot-blot assay using gamma-irradiated strain RB51 bacteria for its specificity and sensitivity to detect antibody responses of cattle vaccinated with strain RB51. Dot-blot titers of sera at a recommended dosage (10(10) colony-forming units) were similar to those of sera from cattle vaccinated with similar numbers of B. abortus strain 19 and greater (P < 0.05) than titers of nonvaccinated cattle. In the first 12 weeks after vaccination with 10(10) colony-forming units of strain RB51, the RB51 dot-blot assay had 100% specificity for titers of 80 or less and a 53% sensitivity for titers of 160 or greater. Sensitivity of the RB51 dot-blot assay peaked at 4 weeks after vaccination with 10(10) colony-forming units of strain RB51. Dot-blot responses of sera from cattle vaccinated with a reduced dosage of strain RB51 (10(9) colony-forming units) did not differ (P > 0.05) from titers of sera from nonvaccinated cattle. Following intraconjunctival challenge with B. abortus strain 2308, titers on the RB51 dot-blot assay did not differ (P > 0.05) between nonvaccinated cattle and cattle vaccinated at calfhood with strain 19 or strain RB51.     

Assessing students' plans for college.

Based on a contemporary cognitive-psychoanalytic theory (control-mastery theory; J. Weiss, H. Sampson, & Mount Zion Psychotherapy Research Group, 1986), this study proposed that college students have plans for college that consist of conscious and unconscious goals and obstructions to be overcome in meeting those goals. The construct of unconscious guilt was used to mediate the dual goals of autonomy and attachment. The idiographic plan-formulation method was adapted to derive plans for 12 sophomore women. Acceptable interjudge reliabilities and criterion validity were demonstrated, and several themes in the goals and obstructions were illustrated. Students worried more about mothers than about fathers, particularly when they perceived the mother as weak or needy. The potential of the method for generating inferences about unconscious process for normative development is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of the neem tree compounds azadirachtin, salannin, nimbin, and 6-desacetylnimbin on ecdysone 20-monooxygenase activity

The effects of azadirachtin, salannin, nimbin, and 6-desacetylnimbin on ecdysone 20-monooxygenase (E-20-M) activity were examined in three insect species. Homogenates of wandering stage third instar larvae of Drosophila melanogaster, or abdomens from adult female Aedes aegypti, or fat body or midgut from fifth instar larvae of Manduca sexta were incubated with radiolabeled ecdysone and increasing concentrations (from 1 x 10(-8) to 1 x 10(-3) M) of the four compounds isolated from seed kernels of the neem tree, Azadirachta indica. All four neem tree compounds were found to inhibit, in a dose-dependent fashion, the E-20-M activity in three insect species. The concentration of these compounds required to elicit a 50% inhibition of this steroid hydroxylase activity in the three insect species examined ranged from approximately 2 x 10(-5) to 1 x 10(-3).     

Neural networks,rational functions,and realization theory

The problem of parametrizing single hidden layer scalar neural networks with continuous activation functions is investigated. A connection is drawn between realization theory for linear dynamical systems, rational functions, and neural networks that appears to be new. A result of this connection is a general parametrization of such neural networks in terms of strictly proper rational functions. Some existence and uniqueness results are derived. Jordan decompositions are developed, which show how the general form can be expressed in terms of a sum of canonical second order sections. The parametrization may be useful for studying learning algorithms.This work was supported by the Australian Research Council, the Australian Telecommunications and Electronics Research Board, and the Boeing Commencai Aircraft Company (thanks to John Moore).