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The intrinsic sources of mortality relate to the ability to meet the metabolic demands of tissue maintenance and repair, ultimately shaping ageing patterns. Anti-ageing mechanisms compete for resources with other functions, including those involved in maintaining functional plasma membranes. Consequently, organisms with smaller cells and more plasma membranes should devote more resources to membrane maintenance, leading to accelerated intrinsic mortality and ageing. To investigate this unexplored trade-off, we reared Drosophila melanogaster larvae on food with or without rapamycin (a TOR pathway inhibitor) to produce small- and large-celled adult flies, respectively, and measured their mortality rates. Males showed higher mortality than females. As expected, small-celled flies (rapamycin) showed higher mortality than their large-celled counterparts (control), but only in early adulthood. Contrary to predictions, the median lifespan was similar between the groups. Rapamycin administered to adults prolongs life; thus, the known direct physiological effects of rapamycin cannot explain our results. Instead, we invoke indirect effects of rapamycin, manifested as reduced cell size, as a driver of increased early mortality. We conclude that cell size differences between organisms and the associated burdens of plasma membrane maintenance costs may be important but overlooked factors influencing mortality patterns in nature., Competing Interests: We declare that we have no competing interests., (© 2023 The Authors.)

Background: Work on the Act on the Profession of Physiotherapist had been conducted since the 1990s. However, it was not until October 2015 that the legal regulations were eventually introduced, following which physiotherapists gained professional independence and became a profession of public trust. The aim of the study was to assess the factors influencing the knowledge of these legal regulations among physiotherapists., Material and Methods: The study involved 399 physiotherapists and physiotherapy students (28.8±5.9 years old) who completed an anonymous questionnaire, in the form of a knowledge test, consisting of 24 questions on the general aspects of the reference Act., Results: Overall, 30.3% of the respondents proved to have a significant knowledge about the rights and obligations resulting from the Act. The physiotherapists who were entered into the National Register of Physiotherapists (2.6 times) and residents of large cities (1.8 times) had a greater knowledge of the Act. There was a correlation between seniority and gender, and the knowledge of legal regulations., Conclusions: The main factors influencing the state of knowledge about the Act are the entry to the National Register of Physiotherapists, the place of residence and seniority. This proves better access to up-to-date information in cities and a greater interest in the Act among those people who have obtained the right to practice their profession. Med Pr. 2021;72(4):407-14., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)