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  • tensor
  • To identify abnormal white matter projections in patients with nmTBI with cognitive impairments using diffusion tensor magnetic resonance imaging (DTI). (bmj.com)
  • In this article, we discuss the theoretical background for diffusion weighted imaging and diffusion tensor imaging. (rice.edu)
  • Water diffusion in tissue is mathematically characterized by the diffusion tensor, the elements of which contain information about the magnitude and direction of diffusion and is a function of the coordinate system. (rice.edu)
  • The directional dependency is removed by diagonalization of the diffusion tensor, which then yields a set of three eigenvalues and eigenvectors, representing the magnitude and direction of the three orthogonal axes of the diffusion ellipsoid, respectively. (rice.edu)
  • Determination of the principal values of the diffusion tensor and various anisotropic indices provides structural information. (rice.edu)
  • The anisotropy is analyzed by decomposing the diffusion tensor based on symmetrical properties describing the geometry of diffusion tensor. (rice.edu)
  • We further describe diffusion tensor properties in visualizing fiber tract organization of the human brain. (rice.edu)
  • coefficient
  • Expressing diffusion in terms of the measured diffusion coefficient (eigenvalue) in any one direction can lead to errors. (rice.edu)
  • 2009). In this matter, we followed the suggestion of Hukka (1999), who simulated moisture transport in the transversal plane of Scots pine ( Pinus sylvestris ) based on the concept of an effective diffusion coefficient and proposed extending this simulation to moisture contents above the FSP. (scielo.org.ar)
  • The parameters that ultimately determined the relationship between moisture content and moisture flow were calculated by solving the following inverse problem: Given a known drying curve and known moisture distributions in certain sections, we determined the effective diffusion coefficient in order to simulate the drying process using a diffusive transport equation. (scielo.org.ar)
  • terms
  • This study focuses on diffusion models, which are advantageous given their simplicity in terms of the number of physical parameters required and numerical calculations. (scielo.org.ar)
  • process
  • Although classic models of technological development suggest a straightforward linear path from basic research and development to technology commercialization and adoption, in practice technology diffusion is more often a complex and iterative process. (gatech.edu)
  • However, it is increasingly recognized that market failures and strategic interests also exist in the process of technology diffusion. (gatech.edu)
  • Molecular diffusion is a random process involving thermal Brownian motion. (rice.edu)
  • diffusivity
  • Traditionally, in diffusion-weighted imaging (DWI), three gradient-directions are applied, sufficient to estimate the trace of the diffusion tensor or 'average diffusivity', a putative measure of edema . (wikipedia.org)
  • Brian and Sune's group had previously described a fast protocol, referred to as the 1-3-9 scheme, that includes three diffusion directions at a low b-value to determine the mean diffusivity and 9 specific diffusion directions at a higher b-value to calculate mean kurtosis [Hansen et al. (ismrm.org)
  • Lexical
  • In historical linguistics, lexical diffusion is both a phenomenon and a theory. (wikipedia.org)
  • The theory of lexical diffusion stands in contrast to the Neogrammarian hypothesis that a given sound change applies simultaneously to all words in which its context is found. (wikipedia.org)
  • For example, Pulleyblank regards the theoretical formulation of lexical diffusion as presented by Hsieh in Wang 1977 as "so manifestly at odds with any realistic picture of how dialects are inter-related and how innovations spread spatially through a language as to make them totally untenable" (1982: 408). (wikipedia.org)
  • Referring to one of Wang's touchstones of lexical diffusion, Egerod dismisses his theory as a sleight of hand: there is no "massive split" involved, but an error of methodology in accounting for tones. (wikipedia.org)
  • Mazaudon & Lowe conclude a robust critique of lexical diffusion in a similar vein, remarking that "a detailed study of the history of the language can disentangle the reflexes from different sources, and it is not necessary to renounce the principle of regular change for the sake of such cases" (1994: 11). (wikipedia.org)
  • William Labov, in Principles of Linguistic Change, takes the position that there are two types of sound changes: regular sound change (respecting the Neogrammarian hypothesis) and lexical diffusion. (wikipedia.org)
  • Labov lists a typology, according to which certain phenomena are typically or exclusively regular (example, vowel quality changes), while others (example, metathesis, or vowel shortening) tend to follow a lexical diffusion pattern. (wikipedia.org)
  • Paul Kiparsky, in the Handbook of Phonology (Goldsmith editor), argues that under a proper definition of analogy as optimization, lexical diffusion is not a type of sound change. (wikipedia.org)
  • Word Frequency and Lexical Diffusion. (wikipedia.org)
  • displaystyle
  • Unlike classical wavelets whose basis functions are predetermined, diffusion wavelets are adapted to the geometry of a given diffusion operator T {\displaystyle T} (e.g., a heat kernel or a random walk). (wikipedia.org)
  • Moreover, the diffusion wavelet basis functions are constructed by dilation using the dyadic powers (powers of two) of T {\displaystyle T} . These dyadic powers of T {\displaystyle T} diffusion over the space and propagate local relationships in the function throughout the space until they become global. (wikipedia.org)
  • This algorithm constructs the scaling basis functions and the wavelet basis functions along with the representations of the diffusion operator T {\displaystyle T} at these scales. (wikipedia.org)
  • Input: // T {\displaystyle T} is the matrix representation of the diffusion operator. (wikipedia.org)
  • Floyd and Steinberg described a system for performing error diffusion on digital images based on a simple kernel: 1 16 [ − # 7 3 5 1 ] {\displaystyle {\frac {1}{16}}\left[{\begin{array}{ccccc}-&\#&7\\3&5&1\end{array}}\right]} where " − {\displaystyle -} " denotes a pixel in the current row which has already been processed (hence diffusing error to it would be pointless), and "#" denotes the pixel currently being processed. (wikipedia.org)
  • x_{i})=M_{i,j}^{t}\,} One of the main ideas of diffusion framework is that running the chain forward in time (taking larger and larger powers of M {\displaystyle M} ) reveals the geometric structure of X {\displaystyle X} at larger and larger scales (the diffusion process). (wikipedia.org)
  • The reason to introduce the normalization step involving α {\displaystyle \alpha } is to tune the influence of the data point density on the infinitesimal transition of the diffusion. (wikipedia.org)
  • Eddy
  • Because the microscopic processes responsible for atmospheric mixing are too complex to model in detail, atmospheric modelers generally treat atmospheric mixing as a macroscopic "eddy" diffusion process. (wikipedia.org)
  • Photon
  • In modern cosmological theory, diffusion damping, also called photon diffusion damping, is a physical process which reduced density inequalities (anisotropies) in the early universe, making the universe itself and the cosmic microwave background radiation (CMB) more uniform. (wikipedia.org)
  • Thus all damping by electron diffusion is negligible when compared to photon diffusion damping. (wikipedia.org)
  • Photon diffusion was first described in Joseph Silk's 1968 paper entitled "Cosmic Black-Body Radiation and Galaxy Formation", which was published in The Astrophysical Journal. (wikipedia.org)
  • convection
  • In most plasmas, the forces acting on the ions are different from those acting on the electrons, so naively one would expect one species to be transported faster than the other, whether by diffusion or convection or some other process. (wikipedia.org)
  • innovations
  • It is distinct from the diffusion of innovations within a specific culture. (wikipedia.org)
  • Also of interest is the work of American historian and critic Daniel J. Boorstin in his book The Discoverers , in which he provides an historical perspective on the role of explorers in the diffusion of innovations between civilizations . (wikipedia.org)
  • anisotropy
  • Diffusion tensor imaging (DTI) is important when a tissue-such as the neural axons of white matter in the brain or muscle fibers in the heart-has an internal fibrous structure analogous to the anisotropy of some crystals. (wikipedia.org)
  • From the diffusion tensor, diffusion anisotropy measures such as the fractional anisotropy (FA), can be computed. (wikipedia.org)
  • This reduction in anisotropy is the damping of diffusion damping. (wikipedia.org)
  • process of diffusion
  • This demo is repeated in cold water and hot water to study the effect of temperature on the process of diffusion. (bu.edu)
  • TSC acts to increase the rate at which oxygen moves through blood plasma by the process of diffusion, a phenomenon that forms the basis for the company's name. (wikipedia.org)
  • coefficients
  • An excellent method for the measurement of self-diffusion coefficients is pulsed field gradient (PFG) NMR, where no isotopic tracers are needed. (wikipedia.org)
  • Mechanism
  • Kulturkugel " (a German compound meaning "culture bullet", coined by J. P. Mallory ), a mechanism suggested by Mallory to model the scale of invasion vs. gradual migration vs. diffusion. (wikipedia.org)
  • An example of a situation in which bulk motion and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration known as breathing. (wikipedia.org)
  • occur
  • However, there sometimes occur so-called quasi-steady states, where the diffusion process does not change in time, where classical results may locally apply. (wikipedia.org)
  • typically
  • Diffusion kurtosis imaging (DKI) increases sensitivity to microstructural changes by extending the diffusion signal expression to account for non-Gaussian effects, but it typically requires time-consuming acquisitions with high diffusion weighting. (ismrm.org)
  • algorithm
  • Unlike many other halftoning methods, error diffusion is classified as an area operation, because what the algorithm does at one location influences what happens at other locations. (wikipedia.org)
  • The simplest algorithm is exactly like one dimensional error diffusion, except half the error is added to the next pixel, and half of the error is added to the pixel on the next line below. (wikipedia.org)
  • Compared with other methods, the diffusion maps algorithm is robust to noise perturbation and is computationally inexpensive. (wikipedia.org)
  • substrate
  • A Diffusion limited enzyme is an enzyme which catalyses a reaction so efficiently that the rate limiting step is that of substrate diffusion into the active site , or product diffusion out. (wikipedia.org)
  • The theory of diffusion-controlled reaction was originally utilized by R.A. Alberty, Gordon Hammes , and Manfred Eigen to estimate the upper limit of enzyme-substrate reaction. (wikipedia.org)
  • A detailed comparison between the simplified Alberty-Hammes-Eigen's model ( a ) and the Chou's model ( b ) in calculating the diffusion-controlled reaction rate of enzyme with its substrate, or the upper limit of enzyme-substrate reaction, was elaborated in the paper. (wikipedia.org)
  • A diffusion transistor is a bipolar junction transistor (BJT) formed by diffusing dopants into a semiconductor substrate. (wikipedia.org)
  • Plasma
  • The plasma diffusion across the magnetic field is an important topic in magnetic confinement of fusion plasma. (wikipedia.org)
  • The Hsu diffusion predicts the 1/B3/2 scaling, that is presumably the best confinement scenario in magnetized plasma. (wikipedia.org)
  • The primary effects on the diffusion length are from the properties of the plasma in question: different sorts of plasma may experience different sorts of diffusion damping. (wikipedia.org)
  • traits
  • Indirect diffusion happens when traits are passed from one culture through a middleman to another culture, without the first and final cultures being in direct contact. (wikipedia.org)
  • occurs
  • Direct diffusion occurs when two cultures are very close to each other, resulting in intermarriage, trade, and even warfare. (wikipedia.org)
  • Forced diffusion occurs when one culture subjugates (conquers or enslaves) another culture and forces its own customs on the conquered people. (wikipedia.org)
  • Oxygen
  • Gainer is the inventor of the company's platform technology of oxygen diffusion-enhancing compounds and its lead drug, trans sodium crocetinate (TSC). (wikipedia.org)
  • TSC and other oxygen diffusion-enhancing compounds, including bipolar trans carotenoid salts (the subclass to which TSC belongs), have been investigated by Diffusion Pharmaceuticals for treatment of conditions associated with reduced oxygen availability in tissues (hypoxia). (wikipedia.org)
  • Gainer invented the concept of oxygen diffusion-enhancing compounds and its specific embodiment, TSC, while a Professor of Chemical Engineering at the University of Virginia. (wikipedia.org)
  • Before TSC's invention, he and colleagues conducted research on the effects of oxygen diffusion-enhancing compounds in various animal disease models, including atherosclerosis, arthritis and cancer. (wikipedia.org)
  • With the invention of TSC, their research turned to the potential use of this synthetic oxygen diffusion-enhancing compound for the improved treatment of hemorrhagic shock (shock caused by the loss of a large volume of blood) on the battlefield. (wikipedia.org)
  • bipolar
  • Between 2008 and 2017, Diffusion Pharmaceuticals expanded its intellectual property portfolio, having been awarded new patents (in the United States and internationally) that covered the synthesis and uses of bipolar trans carotenoid salts and related compounds in peripheral artery disease, cancer and other indications. (wikipedia.org)
  • theories
  • Rogers (1962) states that the purpose of diffusion theories is to accelerate the process associated with the acceptance of new ideas. (ou.edu)
  • theory
  • Rogers (1962) diffusion of innovation theory provides insight on how to communicate with large groups of people through interpersonal communication. (ou.edu)
  • Understanding the adoption lifecycle of innovation can be characterised using Everett Rogers' Diffusions of Innovation theory. (youtube.com)
  • Diffusion wavelets are an extension of classical wavelet theory from harmonic analysis. (wikipedia.org)
  • examples
  • Examples of diffusion include the spread of the war chariot and iron smelting in ancient times, and the use of automobiles and Western business suits in the 20th century. (wikipedia.org)
  • Students are asked to write down and share other examples of diffusion experienced in everyday life. (bu.edu)
  • artifacts
  • One dimensional error diffusion tends to have severe image artifacts that show up as distinct vertical lines. (wikipedia.org)
  • Two dimensional error diffusion reduces the visual artifacts. (wikipedia.org)
  • Recently, we talked with Drs. Jelle Veraart, Els Fieremans, and Dmitry Novikov to learn more about how they use regularization functions to mitigate artifacts induced by Gibbs ringing in diffusion MRI. (ismrm.org)
  • example
  • The sample image at the start of this article is an example of two dimensional error diffusion. (wikipedia.org)
  • An example of direct diffusion is between the United States and Canada , where the people living on the border of these two countries engage in hockey, which started in Canada, and baseball, which is popular in American culture. (wikipedia.org)
  • Some example applications of diffusion: Sintering to produce solid materials (powder metallurgy, production of ceramics) Chemical reactor design Catalyst design in chemical industry Steel can be diffused (e.g., with carbon or nitrogen) to modify its properties Doping during production of semiconductors. (wikipedia.org)
  • The base formed beyond it because of the more rapid diffusion of the acceptor (for example, aluminum). (wikipedia.org)
  • gradient
  • Diffusion gradient" redirects here. (wikipedia.org)
  • More extended DTI scans derive neural tract directional information from the data using 3D or multidimensional vector algorithms based on six or more gradient directions, sufficient to compute the diffusion tensor . (wikipedia.org)