96,459 research outputs found
Cognitive science and epistemic openness
Recent findings in cognitive science suggest that the epistemic subject is more complex and epistemically porous than is generally pictured. Human knowers are open to the world via multiple channels, each operating for particular purposes and according to its own logic. These findings need to be understood and addressed by the philosophical community. The current essay argues that one consequence of the new findings is to invalidate certain arguments for epistemic anti-realism
Are there optical communication channels in the brain?
Despite great progress in neuroscience, there are still fundamental
unanswered questions about the brain, including the origin of subjective
experience and consciousness. Some answers might rely on new physical
mechanisms. Given that biophotons have been discovered in the brain, it is
interesting to explore if neurons use photonic communication in addition to the
well-studied electro-chemical signals. Such photonic communication in the brain
would require waveguides. Here we review recent work [S. Kumar, K. Boone, J.
Tuszynski, P. Barclay, and C. Simon, Scientific Reports 6, 36508 (2016)]
suggesting that myelinated axons could serve as photonic waveguides. The light
transmission in the myelinated axon was modeled, taking into account its
realistic imperfections, and experiments were proposed both in-vivo and
in-vitro to test this hypothesis. Potential implications for quantum biology
are discussed.Comment: 13 pages, 5 figures, review of arXiv:1607.02969 for Frontiers in
Bioscience, updated figures, new references on existence of opsins in the
brain and experimental effects of light on neuron
Postulates on electromagnetic activity in biological systems and cancer
A framework of postulates is formulated to define the existence, nature, and function of a coherent state far from thermodynamic equilibrium in biological systems as an essential condition for the existence of life. This state is excited and sustained by energy supply. Mitochondria producing small packets of energy in the form of adenosine and guanosine triphosphate and strong static electric field around them form boundary elements between biochemical-genetic and physical processes. The transformation mechanism of chemical energy into useful work for biological needs and the excitation of the coherent state far from thermodynamic equilibrium are fundamental problems. The exceptional electrical polarity of biological objects and long-range interactions suggest a basic role of the endogenous electromagnetic field generated by living cells. The formulated postulates encompass generation, properties and function of the electromagnetic field connected with biological activity and its pathological deviations. Excited longitudinal polar oscillations in microtubules in eukaryotic cells generate the endogenous electromagnetic field. The metabolic activity of mitochondria connected with water ordering forms conditions for excitation. The electrodynamic field plays an important role in the establishment of coherence, directional transport, organization of morphological structures, interactions, information transfer, and brain activity. An overview of experimental results and physical models supporting the postulates is included. The existence of the endogenous biological electromagnetic field, its generation by microtubules and supporting effects produced by mitochondria have a reasonable experimental foundation. Cancer transformation is a pathological reduction of the coherent energy state far from thermodynamic equilibrium. Malignancy, i.e. local invasion and metastasis, is a direct consequence of mitochondrial dysfunction, disturbed microtubule polar oscillations and the generated electromagnetic field
Metallic tube type energy absorbers: a synopsis
This paper presents an overview of energy absorbers in the form of tubes in which the material used is predominantly mild steel and/or aluminium. A brief summary is also made of frusta type energy absorbers. The common modes of deformation such as lateral and axial compression, indentation and inversion are reviewed. Theoretical, numerical and experimental methods which help to understand the behaviour of such devices under various loading conditions are outlined. Although other forms of energy absorbing materials and structures exist such as composites and honeycombs, this is deemed outside the scope of this review. However, a brief description will be given on these materials. It is hoped that this work will provide a useful platform for researchers and design engineers to gain a useful insight into the progress made over the last few decades in the field of tube type energy absorbers
On Quantum Mechanical Aspects of Microtubules
We discuss possible quantum mechanical aspects of MicroTubules (MT), based on
recent developments in quantum physics.We focus on potential mechanisms for
`energy-loss-free' transport along the microtubules, which could be considered
as realizations of Fr\"ohlich's ideas on the r\^ole of solitons for
superconductivity and/or biological matter. By representing the MT arrangements
as cavities,we present a novel scenario on the formation of macroscopic (or
mesoscopic) quantum-coherent states, as a result of the
(quantum-electromagnetic) interactions of the MT dimers with the surrounding
molecules of the ordered water in the interior of the MT cylinders. We suggest
specific experiments to test the above-conjectured quantum nature of the
microtubular arrangements inside the cell. These experiments are similar in
nature to those in atomic physics, used in the detection of the Rabi-Vacuum
coupling between coherent cavity modes and atoms. Our conjecture is that a
similar Rabi-Vacuum-splitting phenomenon occurs in the MT case.Comment: 26 pages LATEX (minor typos corrected no effect on conclusions
Prescribed pattern transformation in swelling gel tubes by elastic instability
We present a study on swelling-induced circumferential buckling of tubular
shaped gels. Inhomogeneous stress develops as gel swells under mechanical
constraints, which gives rise to spontaneous buckling instability without
external force. Full control over the post-buckling pattern is experimentally
demonstrated. A simple analytical model is developed using elastic energy to
predict stability and post-buckling patterns upon swelling. Analysis reveals
that height to diameter ratio is the most critical design parameter to
determine buckling pattern, which agrees well with experimental and numerical
results.Comment: 32 pages, 7 figure
Platonic model of mind as an approximation to neurodynamics
Hierarchy of approximations involved in simplification of microscopic theories, from sub-cellural to the whole brain level, is presented. A new approximation to neural dynamics is described, leading to a Platonic-like model of mind based on psychological spaces. Objects and events in these spaces correspond to quasi-stable states of brain dynamics and may be interpreted from psychological point of view. Platonic model bridges the gap between neurosciences and psychological sciences. Static and dynamic versions of this model are outlined and Feature Space Mapping, a neurofuzzy realization of the static version of Platonic model, described. Categorization experiments with human subjects are analyzed from the neurodynamical and Platonic model points of view
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