André Cyr

The efficient electrochemical reduction of nitrobenzene and azoxybenzene to aniline in neutral and basic aqueous methanolic solutions at devarda copper and raney nickel electrodes: electrocatalytic hydrogenolysis of NO and NN bonds

The preparative electrochemical reduction of nitrobenzene, phenylhydroxylamine, azoxybenzene, azobenzene, and hydrazobenzene was studied under controlled potential conditions at Devarda copper and Raney nickel electrodes in neutral (E = −0.6 V vs sce) and basic (E = −1.0 V vs sce) aqueous methanolic solutions. The reduction of NB at Devarda copper electrodes was carried out also at constant current (∼ 2.2 A dm−2) in basic aqueous methanol. The lifetime of the Devarda copper electrode was about 21 days under these conditions. In all cases, aniline was obtained in high chemical (85–100%) and current (80–100%) yields, thus showing that hydrogenolysis of the NO bond of phenylhydroxylamine and of the NN bond of hydrazobenzene is an efficient electrochemical process at these electrodes. An electrocatalytic hydrogenation (ECH) mechanism is most probably operating in this hydrogenolysis process. For the reduction of nitrobenzene to phenylhydroxylamine and of azoxybenzene to hydrazobenzene, an ECH mechanism and/or an electronation—protonation (EP) mechanism can be involved.

Plasma LH and androgen levels in the red-winged blackbird (Agelaius phoeniceus) treated with a potent GnRH analogue

1. Low doses of GnRH-A (0.01-0.10-1.0 micrograms) given during the annual testes growth period did not clearly affect plasma LH and androgen levels 10 min following the injection. 2. The first injection of high doses of GnRH-A (2.0-10.0-20.0 micrograms) markedly increased plasma LH and androgen levels measured 10 min following the injection. The increase in plasma LH level was dose-dependent and the maximal LH level was obtained with 10.0 micrograms of GnRH-A. 3. Impairment of the LH response to GnRH-A was assessed by comparing the first and the fourteenth injection of high doses of GnRH-A. Evidences of pituitary gland desensitization are reported since plasma LH levels were reduced following the fourteenth injection in all groups. 4. Plasma androgen levels following high doses of GnRH-A were not clearly affected in red-winged blackbirds.

The impact of dimethoate on rhythms of three granivorous bird species

Abstract Dimethoate is a currently sprayed organophosphate on farmlands. Its effects on endogenous rhythms of three farmland bird species, Savannah Sparrow ( Passerculus sandwichensis ), Song Sparrow ( Melospiza melodia ) and American Goldfinch ( Carduelis tristis ) was studied. Doses of 0.24 g of dimethoate m −2 of seeds were given on the morning of Day 16 of the experiment for treated birds, and removed the next morning. Rhythmic parameters were collected in the form of perch hopping activity for a period of at least 30 days per bird. The treatment reduced significantly the mean daily activity levels of all the treated birds. It was found that dimethoate ingested orally causes temporary rhythm alterations, the mean recovery time from intoxication being 10.0 days, 11.5 days and 9.0 days for Song Sparrows, Savannah Sparrows and American Goldfinches, respectively. Such effects might become critical, if not fatal, in terms of the food finding ability of the animal and the birds would also be more vulnerable to predators.

SITE-SPECIFIC OBSERVATION IN THE BREEDING SEASON IMPROVES THE ABILITY OF CHECKLIST DATA TO TRACK POPULATION TRENDS

Abstract Checklist programs that compile birding observations are potentially useful for population monitoring. Previous analyses showed that trends in Quebec checklist data from migration seasons were significantly correlated with trends from the Breeding Bird Survey (BBS) in Quebec, although agreement of trend magnitudes for individual species was low. Here we analyze Quebec checklist data from the breeding season for comparison, using both the full data set and a subset of data collected at frequently visited (“standard”) sites. Checklist trends from the breeding season for standard sites corresponded much more closely to magnitudes of BBS trends than checklist trends based on all sites, although in both cases, checklists accurately reflected direction of BBS trend in >80% of species. Checklist trends from migration seasons for all sites and for standard sites were similar to each other, and did not correspond as well to BBS trends, probably because different populations were sampled in the two seasons. Checklist programs can be improved for population monitoring purposes by encouraging frequent reporting from standard sites, and by collecting recommended ancillary data that allow analysts to select data most appropriate to their research questions.

Anesthetization of Captive Red-Winged Blackbirds with Mixtures of Alpha-Chloralose and Secobarbital

No standards exist as to the best combination of drugs to improve the speed of narcosis for capturing birds or to prolong unconsciousness for research purposes. Consequently, we anesthetized adult, male red-winged blackbirds (Agelaius phoeniceus) with different concentrations and mixtures of alphachloralose and secobarbital. Several mixtures (mg alpha-chloralose-mg secobarbital/g body mass [BM]; 0.020- 0.025, 0.025-0.025, 0.025-0.30, and 0.020-0.030) induced unconsciousness in 7-8 minutes and maintained it for 7 to >22 hours. Depending on the dosage, period of unconsciousness can be easily shortened or extended with mixtures compared with using alpha-chloralose or secobarbital alone

Pituitary LH content and plasma LH levels following daily GnRH analogue treatment in male red-winged blackbirds (Agelaius phoeniceus)

1. During the 14-day treatment period, plasma LH levels following GnRH analogue (GnRH-A) injections (10.0 micrograms) were significantly reduced after the 6th and the 14th injection. 2. One day post-treatment, the LH pituitary content was significantly reduced in GnRH-A-treated redwings compared to saline-injected controls. 3. Pituitary LH content was significantly higher in GnRH-A treated birds compared to control birds 14 and 28 days post-treatment and plasma LH levels were similar in both groups. 4. Hypersecretion of LH following GnRH-A injections appears to reduce pituitary LH content, acting as a stimulus for its synthesis. 5. These results suggest a higher LH synthesis and storage in the pituitary gland of the GnRH-A-treated birds compared to the control birds during the post-treatment period.

Does visual structural environment influence the periodicity of the circadian activity rhythms in red‐winged blackbirds (Agelaius phoeniceus)?

Abstract In testing for conspecific activity as a possible Zeitgeber, one must often move the animal into a new environment (new cage) or part of its environment must be modified to allow for social contacts. The aim of this work was to determine whether modifications in the visual structural environment alone can influence the periodicity of the activity rhythm of Red‐winged Blackbirds (Agelaius phoeniceus). Six individually caged adult male birds were examined. Their free‐running period was measured under constant conditions in two different environments. Results clearly show that the periodicity remains stable as long as a bird is kept in the same environment, while it is shifted whenever the bird is transfered into an environment which presents a visually different structure. This source of variation should thus be considered more thoroughly in the interpretation of circadian rhythm experiments conducted under constant conditions of light and temperature.