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The spiral is one of Nature's more ubiquitous shape: it can be seen in various media, from galactic geometry to cardiac tissue. In the literature, very specific models are used to explain some of the observed incarnations of these dynamic entities. Barkley [1, 2] first noticed that the range of possible spiral behaviour is caused by the Euclidean symmetry(More)
  • P Boily
  • 1996
Body mass, resting metabolic rates (RMRs), and serum thyroid hormones concentrations of six captive gray seals (Halichoerus grypus) were measured at regular intervals before, during, and after the annual molt. Changes in body mass suggested that the animals had increased energy expenditures during the last stage of the molt. These were associated with(More)
Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory(More)
The present study was aimed at studying energy balance in mice fed a high-fat diet. Albino mice were divided into three groups. One group had free access to the stock diet, whereas the two other groups consumed a high-fat diet. One of the high-fat fed groups was fed ad libitum, whereas the other was offered a restricted amount of the same diet so that its(More)
Here, we describe a laboratory experiment as part of an upper-level vertebrate physiology course for biology majors to investigate the physiological response of vertebrates to osmoregulatory challenges. The experiment involves measuring plasma osmolality and Na+-K+-ATPase activity in gill tissue of teleost fish acclimated to water of differing salinity. We(More)
The spiral is one of Natures more ubiquitous shape: it can be seen in various media, from galactic geometry to cardiac tissue. Spirals have been studied from a dynamical system perspective starting with Barkley's seminal papers linking a wide class of spiral wave dynamics to the Euclidean symmetry of the excitable media in which they are observed [1,2]. But(More)
Rees BB, Boily P, Williamson LAC. Exerciseand hypoxiainduced anaerobic metabolism and recovery: a student laboratory exercise using teleost fish. Adv Physiol Educ 33: 72–77, 2009; doi:10.1152/advan.90188.2008.—Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia),(More)
Spirals are common in Nature: the snail's shell and the ordering of seeds in the sunflower are amongst the most widely-known occurrences. While these are static, dynamic spirals can also be observed in excitable systems such as heart tissue, retina, certain chemical reactions, slime mold aggregates, flame fronts, etc. The images associated with these(More)
Spirals abound in excitable media. Various PDE models have been suggested in order to explain and predict some of the incarnations of these dynamic entities. In two landmark papers, Barkley [1, 2] noticed that a general family of these were caused by the Euclidean symmetry (inherent in the media) of the models. But the experimental universe is un-perfectly(More)