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THE HURDLE. “Genes could not be relevant to embryology until geneticists could explain how identical genes could generate different types of cells. In 1934, T. H. Morgan speculated that every gene, even though present in every cell, might not be active in every cell.” https://lnkd.in/dQuxg6Y View in LinkedIn

THE PROBLEM OF PERMEABILITY. “However, the nuclear envelope proved to be a permeable barrier. More and more, geneticists began to see some form of differential gene activity as the cause for embryogenesis. Jumping over the nuclear boundary, they claimed embryology as part of their domain as well.” https://lnkd.in/dQuxg6Y View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend and concludes this weekend on a wonderful article about the history of the differences in philosophy between geneticists and embryologists that led to conflicts before the two disciplines came together. The two groups were founded in reductionism and holism respectively, and the two viewpoints were largely unreconcilable. Because of this they took up different camps in the cell and followed different theories. https://lnkd.in/dQuxg6Y View in LinkedIn

The gorgeous lime tree flowers, framed by their silver undersided leaves, are scenting the roads of Girona. View in LinkedIn

BUILDING COMPLEXITY FROM SIMPLICITY. “I argued with him, saying that hierarchically organized stereochemistry, acting according to the key-lock rule, plus electrochemistry as an ornament is an ample basis for the realization of life processes (just like any of the most primitive alphabet is an ample base for expressing the most complex thoughts)". A.D. Sakharov (2011) https://lnkd.in/da7dRTF View in LinkedIn

3D PHYSICS. “We do not yet know of any such 3-D theory that works in that way. Indeed, what surface should we use as the boundary of the universe? One step toward realizing these ideas is to study models that are simpler than our real universe.” https://lnkd.in/draqjTW View in LinkedIn

NEW 3D PHYSICS. “If the physics of our universe is holographic, there would be an alternative set of physical laws, operating on a 3-D boundary of spacetime somewhere, that would be equivalent to our known 4-D physics.” https://lnkd.in/draqjTW View in LinkedIn

FROM 2D TO 4D. “A Universe Painted on Its Boundary. CAN WE APPLY the holographic principle to the universe at large? The real universe is a 4-D system: it has volume and extends in time.” https://lnkd.in/draqjTW View in LinkedIn

LOGICAL SUPPOSITION. “If a 3-D system can be fully described by a physical theory operating solely on its 2-D boundary, one would expect the information content of the system not to exceed that of the description on the boundary.” https://lnkd.in/draqjTW View in LinkedIn

FROM 2D TO 3D. “The holographic principle contends that an analogue of this visual magic applies to the full physical description of any system occupying a 3-D region: it proposes that another physical theory defined only on the 2-D boundary of the region completely describes the 3-D physics.” https://lnkd.in/draqjTW View in LinkedIn