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Topic Review
Biography
Topic Review
Central High-Order Aberrations and Accommodation
High-order aberrations (HOAs) are optical defects that degrade the image quality. They change with factors such as pupil diameter, age, and accommodation. The changes in optical aberrations during accommodation are mainly due to lens shape and position changes. Primary spherical aberration (Z(4.0)) is closely related to accommodation and some studies suggested that it plays an important role in the control of accommodation. Furthermore, central and peripheral HOAs vary with refractive error and seem to influence eye growth and the onset and progression of myopia. The variations of central and peripheral HOAs during accommodation also appear to be different depending on the refractive error. Central and peripheral high-order aberrations are closely related to accommodation and influence the accuracy of the accommodative response and the progression of refractive errors, especially myopia.
554
31 Mar 2023
Topic Review
Centaurus
Centaurus, a prominent southern hemisphere constellation, is one of the largest and most recognizable constellations in the night sky. Named after the centaur Chiron from Greek mythology, Centaurus features the bright Alpha Centauri system, one of the closest star systems to Earth.
408
29 Feb 2024
Topic Review
Centaur (Minor Planet)
Centaurs are small solar system bodies with a semi-major axis between those of the outer planets. They generally have unstable orbits because they cross or have crossed the orbits of one or more of the giant planets; almost all their orbits have dynamic lifetimes of only a few million years, but there is one centaur, (514107) 2015 BZ509, which may be in a stable (though retrograde) orbit. Centaurs typically behave with characteristics of both asteroids and comets. They are named after the mythological centaurs that were a mixture of horse and human. It has been estimated that there are around 44,000 centaurs in the Solar System with diameters larger than 1 kilometer. The first centaur to be discovered, under the definition of the Jet Propulsion Laboratory and the one used here, was 944 Hidalgo in 1920. However, they were not recognized as a distinct population until the discovery of 2060 Chiron in 1977. The largest confirmed centaur is 10199 Chariklo, which at 260 kilometers in diameter is as big as a mid-sized main-belt asteroid, and is known to have a system of rings. It was discovered in 1997. However, the lost centaur 1995 SN55 may be somewhat larger. No centaur has been photographed up close, although there is evidence that Saturn's moon Phoebe, imaged by the Cassini probe in 2004, may be a captured centaur that originated in the Kuiper belt. In addition, the Hubble Space Telescope has gleaned some information about the surface features of 8405 Asbolus. (As of 2008), three centaurs have been found to display comet-like comas: 2060 Chiron, 60558 Echeclus, and 166P/NEAT. Chiron and Echeclus are therefore classified as both asteroids and comets. Other centaurs, such as 52872 Okyrhoe, are suspected of having shown comas. Any centaur that is perturbed close enough to the Sun is expected to become a comet.
944
25 Nov 2022
Topic Review
Cellulose and Microfluidics
Cellulose, a linear polysaccharide, is the most common and renewable biopolymer in nature.
1.1K
10 Feb 2022
Topic Review
Cells Respond to Mechanical Cues of Extracellular Matrix
Extracellular biophysical properties have particular implications for a wide spectrum of cellular behaviors and functions, including growth, motility, differentiation, apoptosis, gene expression, cell–matrix and cell–cell adhesion, and signal transduction including mechanotransduction. Cells not only react to unambiguously mechanical cues from the extracellular matrix (ECM), but can occasionally manipulate the mechanical features of the matrix in parallel with biological characteristics, thus interfering with downstream matrix-based cues in both physiological and pathological processes. Bidirectional interactions between cells and (bio)materials in vitro can alter cell phenotype and mechanotransduction, as well as ECM structure, intentionally or unintentionally. Interactions between cell and matrix mechanics in vivo are of particular importance in a variety of diseases, including primarily cancer.
144
31 Jan 2024
Topic Review
Cell-to-Cell Communication and Information Transfer
Crucial events are generated by criticality, namely by the processes of phase transition from disorder to correlated disorder, affecting key organismal network functions. There is, as suggested by, “a subtle connection between informational exchange within and between networks and the complexity (non-simplicity) of those networks”. West and Grigolini replaced the term complexity with non-simplicity and explain their reasoning by stating that in physics it is easier to understand how phenomena function by the properties or characteristics that are missing, rather than those that are present.
725
22 Sep 2021
Topic Review
Causal Fermion System
The theory of causal fermion systems is an approach to describe fundamental physics. It provides a unification of the weak, the strong and the electromagnetic forces with gravity at the level of classical field theory. Moreover, it gives quantum mechanics as a limiting case and has revealed close connections to quantum field theory. Therefore, it is a candidate for a unified physical theory. Instead of introducing physical objects on a preexisting spacetime manifold, the general concept is to derive spacetime as well as all the objects therein as secondary objects from the structures of an underlying causal fermion system. This concept also makes it possible to generalize notions of differential geometry to the non-smooth setting. In particular, one can describe situations when spacetime no longer has a manifold structure on the microscopic scale (like a spacetime lattice or other discrete or continuous structures on the Planck scale). As a result, the theory of causal fermion systems is a proposal for quantum geometry and an approach to quantum gravity. Causal fermion systems were introduced by Felix Finster and collaborators.
478
28 Oct 2022
Topic Review
Cathodoluminescence of Diamond
Cathodoluminescence (CL) microscopy revealed heterogeneities in diamonds in a very detailed manner with high spatial resolution.
597
21 Jan 2022
Topic Review
Cassiopeia
Cassiopeia, named after the queen in Greek mythology, is a prominent constellation in the northern celestial hemisphere. Known for its distinctive "W" or "M" shape, depending on its orientation in the sky, Cassiopeia is easily recognizable and has been a subject of fascination for astronomers and stargazers throughout history.
332
29 Feb 2024
Biography
Carl H. Brans
Carl Henry Brans (/brænz/; born December 13, 1935) is an American mathematical physicist best known for his research into the theoretical underpinnings of gravitation elucidated in his most widely publicized work, the Brans–Dicke theory. A Texas , born in Dallas, Carl Brans spent his academic career in neighboring Louisiana, graduating in 1957 from Loyola University New Orleans. Having obt
425
01 Dec 2022
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