13 research outputs found
Mechanical Systems: Symmetry and Reduction
Reduction theory is concerned with mechanical systems with symmetries. It constructs a
lower dimensional reduced space in which associated conservation laws are taken out and
symmetries are \factored out" and studies the relation between the dynamics of the given
system with the dynamics on the reduced space. This subject is important in many areas,
such as stability of relative equilibria, geometric phases and integrable systems
Recommended from our members
Developing reflection on values as a foundation for a business career
Students can learn to analyse questions of ethics from the philosophical perspectives of duties, consequences and virtues. This includes the development of empathy and moral courage. Our brains respond to the experiences of others using 'empathy neurons'; we are 'hard-wired' for empathy. Developing moral courage can be linked to the development of empathy, drawing on 'ethics of care' theories. Graduates who express empathy for their colleagues and care for themselves are better equipped to act ethically. We show how learning experiences can enable students to develop problem-solving responses as an alternative to 'fight or flight' reactions to ethical problems. We can help students to develop expertise in ethics by providing them with more opportunities to engage rationally and empathically with ethical problems, through active learning experiences followed by critical reflective processes. Discussing moral exemplars in active learning helps to avoid a cynical view that unethical behaviour is normal. Critical reflection encourages students to make more use of their rational and empathic capacities. The theory of cognitive dissonance helps students to become aware of how we tend to seek information that confirms our decisions while avoiding information that would alert us to ethical hazards
Mechanotransduction in lymphatic endothelial cells
Initial lymphatic vessel endothelial cells are connected to the surrounding elastic fibers by fibrillin anchoring filaments that have been hypothesized to favor interstitial fluid drainage in edema pulling apart interendothelial junctions. We hypothesized a biochemical mechanism involving mechanotransduction. This study was designed to verify whether a relation exists between focal adhesion molecules and anchoring filaments and whether they may transduce extracellular forces to the nucleus. We first performed an immunohistochemical study on human skin cryostat sections to evaluate whether fibrillin and alphav-beta3 integrins, FAK and fibrillin, or alphav-beta3 integrins and FAK co-localize in lymphatic endothelium. We observed that integrins and FAK co-localize and that fibrillin filament attachment sites to endothelial cells merge with these molecules. These data may suggest that fibrillin anchoring filaments are connected to endothelial cells through focal adhesions. Mechanotransduction was investigated applying static stretching to bovine thoracic duct segments and lymphatic endothelial cells cultured on elastic membranes and immunohistochemically evaluating the expression of ERK1/2. Under stretching conditions, ERK1/2 labels the nucleus. Western blotting on cultured cells confirmed the presence of ERK1/2 in stretched cells. Based on our data we speculate that anchoring filaments may trigger a focal adhesion-mediated cascade of mechanotransduction toward the nucleus for genetic modulation and thus contribute to endothelial adaptation to interstitial requirements