Precision and accuracy of Dahl-Lea back-calculated smolt lengths from adult scales of Atlantic salmon Salmo salar.

Using tagged and recaptured Atlantic salmon Salmo salar (n = 106) the present analysis shows that the most commonly applied linear back-calculation method for estimating past length, the Dahl-Lea method, resulted in overestimation of the length of large smolts and underestimation of small smolts. A correction equation (y = 0.53x + 6.23) for estimating true smolt length (y) from lengths back-calculated from adult scale measures (x) to account for these systematic discrepancies is proposed.

Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar).

Migrations between different habitats are key events in the lives of many organisms. Such movements involve annually recurring travel over long distances usually triggered by seasonal changes in the environment. Often, the migration is associated with travel to or from reproduction areas to regions of growth. Young anadromous Atlantic salmon (Salmo salar) emigrate from freshwater nursery areas during spring and early summer to feed and grow in the North Atlantic Ocean. The transition from the freshwater ('parr') stage to the migratory stage where they descend streams and enter salt water ('smolt') is characterized by morphological, physiological and behavioural changes where the timing of this parr-smolt transition is cued by photoperiod and water temperature. Environmental conditions in the freshwater habitat control the downstream migration and contribute to within- and among-river variation in migratory timing. Moreover, the timing of the freshwater emigration has likely evolved to meet environmental conditions in the ocean as these affect growth and survival of the post-smolts. Using generalized additive mixed-effects modelling, we analysed spatio-temporal variations in the dates of downstream smolt migration in 67 rivers throughout the North Atlantic during the last five decades and found that migrations were earlier in populations in the east than the west. After accounting for this spatial effect, the initiation of the downstream migration among rivers was positively associated with freshwater temperatures, up to about 10 °C and levelling off at higher values, and with sea-surface temperatures. Earlier migration occurred when river discharge levels were low but increasing. On average, the initiation of the smolt seaward migration has occurred 2.5 days earlier per decade throughout the basin of the North Atlantic. This shift in phenology matches changes in air, river, and ocean temperatures, suggesting that Atlantic salmon emigration is responding to the current global climate changes.

Evaluation of residual protein on unprocessed and decontaminated dental extraction forceps.

Research into protein contamination of surgical instruments has received increasing attention and has focused on a quantitative analysis, without subsequent identification of these proteins. This study aimed to validate methods for the isolation and identification of instrument protein contamination using extraction forceps as a model. The working ends of used, unclean and decontaminated forceps were boiled in 1% (v/v) SDS and samples precipitated using StrataClean™ resin and Amicon® filtration. Proteins were visualised using SDS-PAGE and identified by mass spectrometry and Western blot. A total of 17 proteins were identified from used, unclean forceps, including blood and bacterial proteins and 2 protein bands from decontaminated forceps samples which could not be accurately identified. The methods described, when used in conjunction with quantitative and surface analysis of instruments, can aid development of cleaning processes by identifying contaminants on used devices that have been removed following cleaning.

In vitro evaluation of cleaning efficacy of detergents recommended for use on dental instruments.

BACKGROUND: The cleaning stage of instrument decontamination processes is a critical control point, and removal of protein deposits is used as a marker of cleaning efficacy. An important factor is the choice of cleaning solution especially in the absence of any defined standards for detergent effectiveness. METHODS: Following method validation, stainless steel tokens were inoculated with reconstituted citrated blood and added to a 24-multiwell plate and immersed in different cleaning solutions for 5 minutes, agitated at 25 (20°) tilts/min at 22°C and at the manufacturers' recommended temperatures. Desorbed protein was measured using the bicinchoninic acid assay. RESULTS: From a starting concentration with a median of 3,700 µg of blood protein of all solutions tested, alkaline detergent (Haemo-sol) removed the largest proportion of protein (median, 2,070 µg), and surgical handwash removed the least protein (median, 0 µg). Reverse osmosis water demonstrated useful blood-removing properties with a median of 1,421 µg. CONCLUSION: The cleaning system we utilized is a simple, inexpensive method to compare the cleaning efficacies of detergents and may be used as a first stage in benchmarking cleaning efficacy of detergents. Not all solutions used in cleaning dental instruments are efficacious at removal of blood.