Variation in the psychosocial determinants of the intention to prescribe hormone therapy prior to the release of the Women's Health Initiative trial: a survey of general practitioners and gynaecologists in France and Quebec

BACKGROUND: Theory-based approaches are advocated to improve our understanding of prescription behaviour. This study is an application of the theory of planned behaviour (TPB) with additional variables. It was designed to assess which variables were associated with the intention to prescribe hormone therapy (HT). In addition, variations in the measures across medical specialities (GPs and gynaecologists) and across countries (France and Quebec) were investigated. METHODS: A survey among 2,000 doctors from France and 1,044 doctors from Quebec was conducted. Data were collected by means of a self-administered questionnaire. A clinical vignette was used to elicit doctors' opinions. The following TPB variables were assessed: attitude, subjective norm, perceived behavioural control, attitudinal beliefs, normative beliefs and power of control beliefs. Additional variables (role belief, moral norm and practice pattern-related factors) were also assessed. A stepwise logistic regression was used to assess which variables were associated with the intention to prescribe HT. GPs and gynaecologists were compared to each other within countries and the two countries were compared within the specialties. RESULTS: Overall, 1,085 doctors from France returned their questionnaire and 516 doctors from Quebec (response rate = 54% and 49%, respectively). In the overall regression model, power of control beliefs, moral norm and role belief were significantly associated with intention (all at p < 0.0001). The models by specialty and country were: for GPs in Quebec, power of control beliefs (p < 0.0001), moral norm (p < 0.01) and cytology and hormonal dosage (both at p < 0.05); for GPs in France, power of control beliefs and role belief (both at p < 0.0001) and perception of behavioural control (p < 0.05) and cessation of menses (p < 0.01); for gynaecologists in Quebec, moral norm and power of control beliefs (both at p = 0.01); and for gynaecologists in France, power of control beliefs (p < 0.0001), and moral norm, role belief and lipid profile (all at p < 0.05). CONCLUSION: In both countries, compared with GPs, intention to prescribe HT was higher for gynaecologists. Psychosocial determinants of doctors' intention to prescribe HT varied according to the specialty and the country thus, suggesting an influence of contextual factors on these determinants

Ice viscosity is more sensitive to stress than commonly assumed

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Millstein, J. D., Minchew, B. M., & Pegler, S. S. Ice viscosity is more sensitive to stress than commonly assumed. Communications Earth & Environment, 3(1), (2022): 57, https://doi.org/10.1038/s43247-022-00385-x.Accurate representation of the viscous flow of ice is fundamental to understanding glacier dynamics and projecting sea-level rise. Ice viscosity is often described by a simple but largely untested and uncalibrated constitutive relation, Glen’s Flow Law, wherein the rate of deformation is proportional to stress raised to the power n. The value n = 3 is commonly prescribed in ice-flow models, though observations and experiments support a range of values across stresses and temperatures found on Earth. Here, we leverage recent remotely-sensed observations of Antarctic ice shelves to show that Glen’s Flow Law approximates the viscous flow of ice with n = 4.1 ± 0.4 in fast-flowing areas. The viscosity and flow rate of ice are therefore more sensitive to changes in stress than most ice-flow models allow. By calibrating the governing equation of ice deformation, our result is a pathway towards improving projections of future glacier change..D.M. was partially funded through an NSF Graduate Research Fellowship. J.D.M. and B.M.M. where partially funded through NSF-NERC award 1853918. B.M.M. received additional funding through NSF-NERC award 1739031

Stability of ice shelves and ice cliffs in a changing climate

The largest uncertainty in future sea-level rise is loss of ice from the Greenland and Antarctic Ice Sheets. Ice shelves, freely floating platforms of ice that fringe the ice sheets, play a crucial role in restraining discharge of grounded ice into the ocean through buttressing. However, since the 1990s, several ice shelves have thinned, retreated, and collapsed. If this pattern continues, it could expose thick cliffs that become structurally unstable and collapse in a process called marine ice cliff instability (MICI). However, the feedbacks between calving, retreat, and other forcings are not well understood. Here we review observed modes of calving from ice shelves and marine-terminating glaciers, and their relation to environmental forces. We show that the primary driver of calving is long-term internal glaciological stress, but as ice shelves thin they may become more vulnerable to environmental forcing. This vulnerability—and the potential for MICI—comes from a combination of the distribution of preexisting flaws within the ice and regions where the stress is large enough to initiate fracture. Although significant progress has been made modeling these processes, theories must now be tested against a wide range of environmental and glaciological conditions in both modern and paleo conditions. ▪ Ice shelves, floating platforms of ice fed by ice sheets, shed mass in a near-instantaneous fashion through iceberg calving.▪ Most ice shelves exhibit a stable cycle of calving front advance and retreat that is insensitive to small changes in environmental conditions.▪ Some ice shelves have retreated or collapsed completely, and in the future this could expose thick cliffs that could become structurally unstable called ice cliff instability.▪ The potential for ice shelf and ice cliff instability is controlled by the presence and evolution of flaws or fractures within the ice.</div