20,747 research outputs found
Overcoming the Newtonian Paradigm: The Unfinished Project of Theoretical Biology from a Schellingian Perspective
Defending Robert Rosen’s claim that in every confrontation between physics and biology it is physics that
has always had to give ground, it is shown that many of the most important advances in mathematics
and physics over the last two centuries have followed from Schelling’s demand for a new physics that
could make the emergence of life intelligible. Consequently, while reductionism prevails in biology, many
biophysicists are resolutely anti-reductionist. This history is used to identify and defend a fragmented but
progressive tradition of anti-reductionist biomathematics. It is shown that the mathematicoephysico
echemical morphology research program, the biosemiotics movement, and the relational biology of
Rosen, although they have developed independently of each other, are built on and advance this antireductionist tradition of thought. It is suggested that understanding this history and its relationship to the broader history of post-Newtonian science could provide guidance for and justify both the integration of these strands and radically new work in post-reductionist biomathematics
Aerospace medicine and biology: A continuing bibliography with indexes (supplement 339)
This bibliography lists 105 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during July 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance
Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides
Two-dimensional (2D) materials have become a fertile playground for the
exploration and manipulation of novel collective electronic states. Recent
experiments have unveiled a variety of robust 2D orders in highly-crystalline
materials ranging from magnetism to ferroelectricity and from superconductivity
to charge density wave (CDW) instability. The latter, in particular, appears in
diverse patterns even within the same family of materials with isoelectronic
species. Furthermore, how they evolve with dimensionality has so far remained
elusive. Here we propose a general framework that provides a unfied picture of
CDW ordering in the 2H polytype of four isoelectronic transition metal
dichalcogenides 2H-MX (M=Nb, Ta and X=S, Se). We first show experimentally
that whilst NbSe exhibits a strongly enhanced CDW order in the 2D limit,
the opposite trend exists for TaSe and TaS, with CDW being entirely
absent in NbS from its bulk to the monolayer. Such distinct behaviours are
then demonstrated to be the result of a subtle, yet profound, competition
between three factors: ionic charge transfer, electron-phonon coupling, and the
spreading extension of the electronic wave functions. Despite its simplicity,
our approach can, in essence, be applied to other quasi-2D materials to account
for their CDW response at different thicknesses, thereby shedding new light on
this intriguing quantum phenomenon and its underlying mechanisms
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