Combination ecotoxicity and testing of common chemical discharges to sewer using the Vibrio fischeri luminescence bioassay

In order to investigate possible synergistic or antagonistic (more or less than additive) toxicity effects, mixtures of chemicals were tested in water using a microbial bioassay. Ten toxicants (3,4-dichloroaniline, 3,5- dichlorophenol, cadmium, chromium, copper, Lindane, linear alkylbenzene sulphonate, pentachlorophenol, toluene, zinc) were chosen on the basis of their common occurrence in industrial effluents within local waste water treatment plants. These toxicants also cover a wide range of modes of toxic action, namely, polar and non-polar narcosis, membrane disruption, respiratory disruption, uncouplers of oxidative phosphorylation, biochemical disruption and enzyme inhibition. Efficient screening for possible combination toxicity between toxicants involved testing the chemicals both singly and in triplet combinations. The triplets were based on four replicates of a balanced incomplete block design (BIB). A standardised Vibrio fischeri rapid toxicity bioluminescence assay was used. The combinations tested showed that only one mixture was found to be significantly more toxic than expected from the pure singletoxicant results. Two triplets were significantly less toxic. Further tests on the more toxic triplet showed that the effect was due to only one of the 45 pairs originally screened. It is concluded that synergistic effects in combinations of toxicants are rather rare in bioluminescence systems utilising common effluents discharged to sewer

Towards a combined Rotational-Differential Cryptanalytic Framework

In this report, we suggest a new cryptanalytic framework of constructing distinguishers which can be eventually extended to full attacks in the related-key scenario. We name this new paradigm as ”Relational Cryptanalysis”. The main idea is to exhibit the non-randomness of a given encryption algorithm by observing the propagation of specific sets of plaintexts of the form (P,P′) such that these pairs satisfy some rotational and differential properties of the form R1(P) = P′ and P ⊕ P′ ∈ ∆P, for some rotational symmetry R1 and fixed set of differences ∆P . Except of rotational and differential properties, we can add any other relation which seems to hold for a reduced number of rounds of the cryptographic primitive we study. Intuitively, we expect that by adding more relations we increase the observed probability of the propagation and this result to stronger statistical distinguishers

A financial econometric analysis of the determinants of interest rate risk in the US

We introduce a macroeconomic system which we use for interest rate determination, after which we generate the interest rate risk premium. Considering this risk premium function, we investigate, test and determine the macro-variables which affect the interest rate risk premia by using a GARCH(p,q) and an ARCH-M model. The empirical results examine ten different interest rate risk premia and fifteen factors. Factors with significant effects on risk premia are: the real risk-free rate of interest, the inflation rate, the unemployment rate, the growth of GDP and industrial production, the growth of national debt and current account deficit, the money supply growth, the yield differentials on S-T and L-T securities and other variables. The conclusion is that, if we can decrease the volatility of the aforementioned determinants, we can also reduce interest rate risk and, consequently, the risk premium, thus, improving social interest.peer-reviewe

Stock Picking Techniques: The Practice Of Applied Money Managers

This study examines the diverse methods practitioners of money management use in order to choose stock investments. The authors discover they use discounted cash flow, multiples, balance sheet approaches. Additionally, they consider industry forces such as demographics and psychographics

Comparative antibacterial potential of selected aldehyde-based biocides and surfactants against planktonic Pseudomonas fluorescens

The antimicrobial efficacy of two aldehydebased biocides (glutaraldehyde, GTA, and orthophthalaldehyde, OPA) and two surfactants (cetyltrimethyl ammonium bromide, CTAB, and sodium dodecyl sulphate, SDS) was tested against planktonic Pseudomonas fluorescens. The antimicrobial effects were evaluated by respiratory activity as a measure of the oxygen uptake rate, adenosine triphosphate (ATP) release, outer membrane proteins (OMP) expression and cellular colour changes. The results were compared with the bacterial characteristics without chemical treatment. Tests in the presence of bovine serum albumin (BSA), in order to mimic a disinfection process in the real situation under dirty conditions, were performed according to the European Standard EN-1276. P. fluorescens was completely inactivated with OPA (minimum bactericidal concentration, MBC = 0.5 mM) and CTAB (MBC = 5 mM) and was resistant to GTA and SDS. Only CTAB promoted cellular disruption and consequent ATP release. The antimicrobial action of the chemicals tested was significantly reduced when BSA was introduced into the bacterial cultures, increasing markedly the MBC values. Additionally, the presence of BSA acted as a disruption protective agent when CTAB was applied and stimulated the bacterial respiratory activity when lower concentrations of SDS were tested. The OMP of the bacterial cells was affected by the application of both surfactants. OMP expression remained unaltered after biocide treatment. Bacterial colour change was noticed after treatment with biocides and surfactants. In summary, P. fluorescens was extremely resistant to GTA and SDS, with antimicrobial action being quenched markedly by the reaction with BSA.Instituto de Biotecnologia e Química Fina (IBQF).Fundação para a Ciência e a Tecnologia (FCT) - (Project CHEMBIO - POCI/BIO/61872/2004

Domain wall fermions for planar physics

In 2+1 dimensions, Dirac fermions in reducible, i.e. four-component representations of the spinor algebra form the basis of many interesting model field theories and effective descriptions of condensed matter phenomena. This paper explores lattice formulations which preserve the global U(2N) symmetry present in the massless limit, and its breakdown to U(N)xU(N) implemented by three independent and parity-invariant fermion mass terms. I set out generalisations of the Ginsparg-Wilson relation, leading to a formulation of an overlap operator, and explore the remnants of the global symmetries which depart from the continuum form by terms of order of the lattice spacing. I also define a domain wall formulation in 2+1+1d, and present numerical evidence, in the form of bilinear condensate and meson correlator calculations in quenched non-compact QED using reformulations of all three mass terms, to show that U(2N) symmetry is recovered in the limit that the domain-wall separation L tends to infinity. The possibility that overlap and domain wall formulations of reducible fermions may coincide only in the continuum limit is discussed

Optimization for the Production of Surfactin with a New Synergistic Antifungal Activity

-surfactin and the optimization of its production by the response surface method.O. A production of 134.2 mg/L, which were in agreement with the prediction, was observed in a verification experiment. In comparison to the production of original level (88.6 mg/L), a 1.52-fold increase had been obtained.-surfactin