Fast seismic inversion

Geophysics ◽  
1983 ◽  
Vol 48 (10) ◽  
pp. 1371-1372 ◽  
Author(s):  
W. Keith McClary
Keyword(s):  
Inverse Problem ◽  
Layered Medium ◽  
Normal Incidence ◽  
Seismic Inversion ◽  
Reflection Coefficients ◽  
Type B ◽  
Layer Model ◽  
Type C ◽  
Layer Problem

The equal traveltime layer model of a horizontally layered medium with waves at normal incidence is used to solve the inverse problem (determination of the reflection coefficients and fundamental polynomials from the surface response) by an efficient algorithm using [Formula: see text] computations for N layers. The idea is to reduce the N‐layer problem to two similar problems of N/2 layers each plus additional computations of type B and C. Type B computes the data for the second problem from the result of the first and type C combines the results. For [Formula: see text] the reduction is carried out k times leading to N trivial one‐layer problems plus more computations of type B and C, which are polynomial multiplications or discrete convolutions. The improvement over the [Formula: see text] computations required by recursive methods comes from using the fast Fourier transform to perform the convolutions.

APPLICATION OF DYNAMIC PROGRAMMING TO THE PROBLEM OF PLANE WAVE PROPAGATION IN A LAYERED MEDIUM

Geophysics ◽  
1966 ◽  
Vol 31 (6) ◽  
pp. 1037-1048 ◽  
Author(s):  
E. K. Darby ◽  
Norman S. Neidell
Keyword(s):  
Dynamic Programming ◽  
Wave Propagation ◽  
Plane Wave ◽  
Layered Medium ◽  
Normal Incidence ◽  
Two Stage ◽  
Stage Process ◽  
Plane Wave Propagation ◽  
Recursive Relations ◽  
Layer Problem

The philosophy of dynamic programming is applied to the problem of plane wave propagation at normal incidence in a layered medium. Using the intuitive concepts of reflection, transmission, and delays, the problem is reduced to a two‐stage process or a two‐layer problem where one of the layers is inhomogeneous. A solution in terms of recursive relations is obtained and a method for compactly describing complex configurations of layers is given. The recursive relations proceed forward in time.

Classification of small type B/C follicles as primordial follicles in mature rats

Reproduction ◽  
2000 ◽  
pp. 43-48 ◽  
Author(s):  
S Meredith ◽  
G Dudenhoeffer ◽  
K Jackson
Keyword(s):  
Dna Synthesis ◽  
Granulosa Cells ◽  
Single Layer ◽  
Reliable Indicator ◽  
Type B ◽  
Primordial Follicles ◽  
Type C

In the present study, follicles were classified according to the morphology of their granulosa cells. Type B follicles contained only flattened granulosa cells; type B/C follicles had a mixture of flattened and cuboidal granulosa cells in a single layer, and type C follicles had a single layer of cuboidal granulosa cells. The primary objectives of the study were to determine whether 5-bromo-2-deoxyuridine incorporation into type B/C follicles was a marker for initiation of growth and how long type B/C follicles could remain at the same stage before transformation to type C follicles. Female Holtzman rats received bromo-deoxyuridine for 7 days. After the infusion (day minipumps were removed = day 0), rats were ovariectomized on days 0 (n = 9), 30 (n = 8), 90 (n = 8) and 150 (n = 9). The numbers of type B, B/C and C follicles within one ovary were determined using modified fractionator counting. Analysis over all times demonstrated that there were more (P < 0.0001) type B/C (941 +/- 61 per ovary) than type C (140 +/- 18 per ovary) or type B (159 +/- 19 per ovary) follicles. The numbers of type B and type C follicles did not differ from each other at any time. Only one of 34 rats evaluated had bromo-deoxyuridine-labelled type B follicles. On day 150, 57% of the bromo-deoxyuridine-labelled type B/C follicles remained from day 0. It is concluded that (1) DNA synthesis in granulosa cells of type B/C follicles is not a reliable indicator of impending growth; and (2) type B and type B/C follicles are both components of the pool of primordial follicles.

Determination of the optimal filtering parameters to find close associations of seismic inversion attributes

2020 ◽  
Vol 4 ◽  
pp. 27-29
Author(s):  
A.V. Novoyavchev ◽  
◽  
A.A. Kleimenov ◽  
M.Yu. Tokarev ◽  
K.M. Myatchin ◽  
...  
Keyword(s):  
Seismic Inversion ◽  
Optimal Filtering

Determination of an impulsive diffusion operator from interior spectral data

Analysis ◽  
2020 ◽  
Vol 40 (1) ◽  
pp. 39-45
Author(s):  
Yasser Khalili ◽  
Dumitru Baleanu
Keyword(s):  
Inverse Problem ◽  
Spectral Data ◽  
Potential Functions ◽  
Half Line ◽  
Internal Point ◽  
Diffusion Operator ◽  
Impulsive Diffusion

AbstractIn the present work, the interior spectral data is used to investigate the inverse problem for a diffusion operator with an impulse on the half line. We show that the potential functions {q_{0}(x)} and {q_{1}(x)} can be uniquely established by taking a set of values of the eigenfunctions at some internal point and one spectrum.

scholarly journals Mice carrying an analogous heterozygous dynamin 2 K562E mutation that causes neuropathy in humans develop predominant characteristics of a primary myopathy

2020 ◽  
Vol 29 (8) ◽  
pp. 1253-1273
Author(s):  
Jorge A Pereira ◽  
Joanne Gerber ◽  
Monica Ghidinelli ◽  
Daniel Gerber ◽  
Luigi Tortola ◽  
...  
Keyword(s):  
Mouse Model ◽  
Treatment Strategies ◽  
Underlying Disease ◽  
Potential Treatment ◽  
Type B ◽  
Disease Mechanism ◽  
Demyelinating Neuropathy ◽  
Charcot Marie Tooth ◽  
Dynamin 2

Abstract Some mutations affecting dynamin 2 (DNM2) can cause dominantly inherited Charcot–Marie–Tooth (CMT) neuropathy. Here, we describe the analysis of mice carrying the DNM2 K562E mutation which has been associated with dominant-intermediate CMT type B (CMTDIB). Contrary to our expectations, heterozygous DNM2 K562E mutant mice did not develop definitive signs of an axonal or demyelinating neuropathy. Rather, we found a primary myopathy-like phenotype in these mice. A likely interpretation of these results is that the lack of a neuropathy in this mouse model has allowed the unmasking of a primary myopathy due to the DNM2 K562E mutation which might be overshadowed by the neuropathy in humans. Consequently, we hypothesize that a primary myopathy may also contribute to the disease mechanism in some CMTDIB patients. We propose that these findings should be considered in the evaluation of patients, the determination of the underlying disease processes and the development of tailored potential treatment strategies.

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