Estimating pregnancy rate from blubber progesterone levels of a blindly biopsied beluga population poses methodological, analytical and statistical challenges.

Beluga (Delphinapterus leucas) from the St. Lawrence Estuary, Canada, have been declining since the early 2000s, suggesting recruitment issues as a result of low fecundity, abnormal abortion rates or poor calf or juvenile survival. Pregnancy is difficult to observe in cetaceans, making the ground truthing of pregnancy estimates in wild individuals challenging. Blubber progesterone concentrations were contrasted among 62 SLE beluga with a known reproductive state (i.e. pregnant, resting, parturient and lactating females), that were found dead in 1997 to 2019. The suitability of a threshold obtained from decaying carcasses to assess reproductive state and pregnancy rate of freshly-dead or free-ranging and blindly-sampled beluga was examined using three statistical approaches and two data sets (135 freshly harvested carcasses in Nunavik, and 65 biopsy-sampled SLE beluga). Progesterone concentrations in decaying carcasses were considerably higher in known-pregnant (mean ± sd: 365 ± 244 ng g-1 of tissue) than resting (3.1 ± 4.5 ng g-1 of tissue) or lactating (38.4 ± 100 ng g-1 of tissue) females. An approach based on statistical mixtures of distributions and a logistic regression were compared to the commonly-used, fixed threshold approach (here, 100 ng g-1) for discriminating pregnant from non-pregnant females. The error rate for classifying individuals of known reproductive status was the lowest for the fixed threshold and logistic regression approaches, but the mixture approach required limited a priori knowledge for clustering individuals of unknown pregnancy status. Mismatches in assignations occurred at lipid content < 10% of sample weight. Our results emphasize the importance of reporting lipid contents and progesterone concentrations in both units (ng g-1 of tissue and ng g-1 of lipid) when sample mass is low. By highlighting ways to circumvent potential biases in field sampling associated with capturability of different segments of a population, this study also enhances the usefulness of the technique for estimating pregnancy rate of free-ranging population.

From traditional to problem-based learning: a case report of complete curriculum reform.

The Sherbrooke School of Medicine, Quebec, has restructured its entire curriculum to make problem-based learning (PBL) the main instructional format. This complete reform is explained both in terms of process and content. The curriculum problems were clearly identified and overcome by a major structural shift-over following the stages of a strategic planning of change. Implementation over a period of 7 years is described according to a four-stage framework: need for change; selection of the PBL solution; planning for implementation; and the full-scale adoption of the PBL method. The programme is described in relation to the congruence of goals, learning and evaluation activities. Initial impact on student learning and evaluation, attracting better quality students, academic staff roles, and on financing the operation are discussed. Changing the undergraduate programme has become an institutional project directed by the Office of the Dean.

Linear IgA dermatosis with severe arthralgia.

Linear IgA dermatosis with severe arthralgia is a rare clinical syndrome. Streptococcal infection may be important in its pathogenesis. The rash and arthralgia respond to dapsone although additional treatment with non-steroidal anti-inflammatory drugs and/or corticosteroids may be necessary. A case is presented which illustrates these features.

[Changes in the global electromyogram during static exercise; effect of age]. / Modifications de l'électromyogramme global lors de l'exercice statique: effets de l'âge.

In normal man, the EMG changes in forearm muscles holding a tension of 30% maximal voluntary strength for 5 minutes are: (1) an increase of integrated EMG, (2) a slight decrease of the median frequency of the EMG power spectrum. These changes are largely reduced with age.

[Cardiovascular changes induced by isometric exercise in aged subjects]. / Modifications cardio-vasculaires induites par l'exercice isométrique chez les sujets âgés.

Blood pressure and heart rate during static contraction of forearm muscles holding a tension of 30% maximal voluntary strength for 5 mn have been measured. Eleven young men and 11 elderly male subjects were used. Maximal voluntary strength is reduced by 19% in elderly subjects. Relative mean cardio-vascular responses were unaffected by age.