Moult speed predicts pairing success in male harlequin ducks

The bright plumage of male ducks in sexually dichromatic species is thought to have evolved through intense sexual selection. This study examined the relationship between the timing and speed of moult into this bright plumage and subsequent mating success of male harlequin ducks, Histrionicus histrionicus. Males that moulted relatively slowly had a lower chance of establishing a pair bond than others. The timing of moult was unrelated to whether a male obtained a mate. Moult speed and timing were not correlated within individual males, but were significantly repeatable in individual males over 2 years. Moult speed probably reflects the condition of males, whereas timing of moult is more likely to be related to the distance to an individual's breeding area, which determines the timing of arrival to the moulting grounds. In waterfowl species that have been studied, males usually form dominance hierarchies before pairing and females tend to choose dominant males. We suggest that male harlequin ducks that moult slowly are poor-quality individuals, which are relegated to subordinate status and are unlikely to attract a mate the following autumn. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Operation of erbium-doped fiber amplifiers and lasers pumped withfrequency-doubled Nd:YAG lasers

An optical amplifier consisting of an erbium-doped germanosilicate fiber optically pumped at 532 nm is described. Negligible excited-state absorption at 532 nm allows efficient pumping, enabling a gain of 34 dB at 1536 nm to be obtained for only 25 mW of pump power. The pulsed pump source produces negligible noise on the small signal if the pump repetition rate is above 10 kHz. Pulsed laser operation is achieved by pumping a Fabry-Perot erbium-doped fiber laser with a frequency-doubled Q-switched Nd:YAG laser. Pulses of 0.9-W peak power and 280-ns duration at 1.538-μm were obtained     

Interaction of L-glutamic acid with human T-lymphocytes

A specific interaction of [3H]Glu with T lymphocytes from the blood of healthy donors (Kd = 0.236 microM) was revealed and described. It was found that unlabeled quisqualate, a structural analogue of L-glutamic acid, and unlabeled dipeptides Ala-Glu, Glu-Ala, and Glu-Glu competitively inhibit the specific binding of [3H]Glu to T lymphocytes (with Ki 0.19, 2.4, 3.4, and 1.2 microM, respectively). Binding experiments with conjugates of labeled and unlabeled glutamic acid with dextran showed that the receptors of [3H]Glu are localized on the outer surface of the plasma membrane of T lymphocytes.     

Localization of telencephalic regions concerned with habituation of cardiac and ventilatory responses associated with arousal in the goldfish (Carassius auratus).

54 goldfish were presented with a light-on stimulus at 2-min intervals, and their cardiac and ventilatory responses were monitored. Normal Ss, Ss with sham operations for telencephalic lesions, and Ss with bilateral electrolytic lesions of the telencephalon (anterior commissural and posterior telencephalic groups) were compared for responsiveness and habituation to regularly presented stimuli. There was no evident difference in responsiveness between the 4 groups, although 3 Ss with lesions in the regions ventralis pars dorsalis and ventralis pars ventralis gave fright responses to novel stimuli. Lesions in posterior telencephalic regions dorsalis pars centralis and ventralis pars intermedialis and at the telencephalic/diencephalic border close to the habenula caused significant impairment of habituation. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence analysis of small cryptic plasmids isolated from Selenomonas ruminantium S20

The degradation kinetics of five glutamine dipeptides in aqueous solution, i.e. glycyl-L-glutamine (Gly-Gln), L-alanyl-L-glutamine (Ala-Gln), L-valyl-L-glutamine (Val-Gln), L-leucyl-L-glutamine (Leu-Gln) and L-isoleucyl-L-glutamine (Ile-Gln), were studied. Stability tests were performed using a stability-indicating high-performance liquid chromatographic assay. Two different Ala-Gln degradation routes, i.e. the cleavage of a peptide bond and the deamination of an amide group, were observed. The degradation was adequately described by pseudo-first-order kinetics. The maximum stability of Ala-Gln was obtained at an approximate pH of 6.0. The pH-rate profile described by specific acid-base catalysis and hydrolysis by water molecules agreed with the experimental results. The activation energy of Ala-Gln at pH 6.0 was determined to be 27. 1kcal mol-1, and the shelf-life (90% remaining) at 25 and 40 degrees C was predicted to be 5.3 years and 7.1 months, respectively. The rate constants of the glutamine dipeptides were influenced by the N-terminal amino acid residue and decreased in the order: Gly-Gln, Ala-Gln, Leu-Gln, Val-Gln and Ile-Gln.     

Comparison of methods to enumerate bacteria in dental unit water lines

Millipore HPC samplers are simple, self-contained test devices that can be used by personnel in dental offices who do not have microbiologic training to easily and economically monitor dental unit water quality without laboratory support. This study evaluated the correlation of HPC samplers to R2A agar for enumerating planktonic bacteria in dental unit treatment water. Eight different dental units were sampled. Five replicates were performed for each media at each dilution. The Pearson correlation coefficient between the R2A agar and HPC sampler is 0.89. These data suggest HPC samplers correlate with conventional laboratory-based R2A culture techniques for determining dental unit water line contamination.