A logical and algebraic treatment of conditional probability

This paper is devoted to a logical and algebraic treatment of conditional probability. The main ideas are the use of non-standard probabilities and of some kind of standard part function in order to deal with the case where the conditioning event has probability zero, and the use of a many-valued modal logic in order to deal probability of an event as the truth value of the sentence is probable, along the lines of Hájeks book [H98] and of [EGH96]. To this purpose, we introduce a probabilistic many-valued logic, called FP(S), which is sound and complete with respect a class of structures having a non-standard extension [0,1] of [0,1] as set of truth values. We also prove that the coherence of an assessment of conditional probabilities is equivalent to the coherence of a suitably defined theory over FP(S) whose proper axioms reflect the assessment itself.Mathematics Subject Classification (2000): 03B50, 06D35     

Maximum Speed of Quantum Gate Operation

We consider a quantum gate, driven by a general time-dependent Hamiltonian, that complements the state of a qubit and then adds to it an arbitrary phase shift. It is shown that the minimum operation time of the gate is

Shape Influence in Buckling of GFRP Pultruded Columns

A theoretical and experimental study on the buckling of pultruded columns under an axial load is reported. The tests were carried out on wide-flange (H-shape) and narrow-flange (I-shape) pultruded structural profiles reinforced with glass fibers (GFRP). The aim of the research was to provide more detailed information on the effective buckling behavior, the interaction between local and global buckling, and the type of failure, considering different slenderness ratios, from 9 to 195. Also, a comparison between the results of a finite-element analysis and experimental data is shown.     

Salt effect on the dissociation constant of acid-base indicators

The effect of the ionic environment on the dissociation constant of acid-base indicators is accounted for by using the specific interaction theory (SIT) of Broensted, Scatchard, and Guggenheim. It is shown that the SIT may be applied to evaluate the activity coefficients of organic ions, regardless of their size and structure, if suitable modifications are introduced.     

Bioluminescent flow sensor for the determination of L-(+)-lactate

The amount of L-lactate in biological fluids (serum, plasma and cerebrospinal fluid) was determined by monitoring the reduced form of nicotinamide adenine dinucleotide (NADH) produced by immobilised lactate dehydrogenase (LDH), with bacterial bioluminescent enzymes immobilised on a separate nylon coil. The LDH catalysed the reaction of L-lactate with NAD; this reaction took place in a nylon coil that preceded the coil for the bioluminescent detection. The co-immobilisation of alanine aminotransferase (ALT) with LDH improved the lactate transformation by 117-183%. The response was linear from 0.1 to 50 micron mol l(-1) at 25 degrees C for the LDH - ALT reactor. The intra- and inter-assay coefficients of variation were less than 5% and the recoveries ranged from 93 to 106%. The results agreed well with those obtained with a spectrophotometric method and with the normal reference values.     

Liquid–solid extraction of butyltin compounds from marine samples

Environmental damage due to organotins (TBT, DBT, MBT) released from antifouling paints is well documented. The concentrations of these compounds in seawater are usually at ppt (parts per 10¹²) levels. Many analytical techniques, including chromatographic and spectrophotometric ones, have been presented in the literature to detect organotins at these low levels. Liquid-liquid extraction is commonly employed as a concentration method. However, it presents some disadvantages during sampling campaigns and requires large volumes of toxic and expensive solvents. In this paper we propose an analytical method based on a liquid-solid extraction procedure that can be easily performed in the field and is characterized by good recoveries and high enrichment factors. Three different solid phases (Carbopack, LC 8 and LC 18) and five different eluting agents (methanol/tropolone, methanol, dichloromethane, hexane and diethyl ether) were evaluated. Carbopack and LC 18 were the most suitable solid phases. Inorganic tin was not retained on these solid phases and a separation of TBT from DBT and MBT was achieved, performing the elution in two steps with methanol and methanol/tropolone. In this way GF AA was suitably employed to obtain butyltin speciation data.