The method consisted in combustion, using a Parr bomb type 1121, of a sediment - tritium free promoter mixture. The proper ratio sediment to promoter in our experiments was between 1:3 and 1:2, higher ratio resulting in unreliable results, due to incomplete combustion of the sample. The described method was used to measure the estuarine sediment sample from the 2nd International OBT Intercompar...

We propose a new complexity measure of space for the BSS model of computation. We define LOGSPACEW and PSPACEW complexity classes over the reals. We prove that LOGSPACEW is included in NC 2 R ∩ PW , i.e. is small enough for being relevant. We prove that the Real Circuit Decision Problem is PR-complete under LOGSPACEW reductions, i.e. that LOGSPACEW is large enough for containing natural algorit...

The Ruedenberg type formula relating the total molecular energy to the sum of orbital energies is examined by using SCC-MO and ab initio D Z M O eigenvalues. Comparison with rigorous ab initio D Z energy expectation values indicates that Ruedenberg 's formula in its original form can not provide semiquantitative information on molecular energetics. Much more promissing in this respect is the el...

Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices...

There is a high regard for peracetic acid (PAA)-based disinfectants in recirculating aquaculture systems (RAS) because of the low risk bioaccumulation, fast degradation with neutral residuals and minimal impact on biofilter performance. However, no-observed-effect concentration Atlantic salmon parr unknown. The present study evaluated effect an acute PAA exposure health welfare by evaluating su...

The effect of serial in vitro subculturing on three pathogenic strains of Saprolegnia parasitica was investigated. The isolates were passed through Atlantic salmon, Salmo salar L. parr, and then re-isolated as single spore colonies. All strains caused infection. The isolate obtained from diseased fish served as a virulent reference culture and was designated 'AP' ('activated through passage'). ...

Laboratory and field ecotoxicology studies clarify levels of pollutants that adversely affect organisms at various life stages. We examined three well-controlled laboratory studies of hexavalent chromium (Cr-VI) toxicity to fertilization, eggs and juvenile Chinook Salmon (Oncorhynchus tshawytscha), to identify effect levels for several endpoints. These studies are relevant to Cr-VI contaminatio...

The Pariser-Parr-Pople Hamiltonian is used to calculate and identify the nature of the low-lying vertical transition energies of polydiacetylene. The model is solved using the density matrix renormalisation group method for a fixed acetylenic geometry for chains of up to 102 atoms. The non-linear optical properties of polydiacetylene are considered, which are determined by the third-order susce...

One of the most clearly defined endocrine changes during the parr-smolt transformation of anadromous salmonids is an increase in plasma levels of thyroid hormones. The role of pineal hormone melatonin in timing and synchronisation of smoltification is widely discussed. The effect of administration of exogenous thyroxine (T4) on plasma melatonin was investigated in juvenile Atlantic salmon (Salm...

Ž . Atlantic salmon Salmo salar parr were subjected to acute handling stresses and growth-monitored for at least 30 days. In fish stressed twice daily, growth rate in weight was 61% lower than Ž y1. controls after 11 days 1.00 vs. 2.57% day and over a 30 day period it was 50% lower than Ž y1. controls 1.53 vs. 3.07% day . In fish stressed once daily, growth rate was 18% lower than Ž y1. control...