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Journal Article

Wide-azimuth marine acquisition by the helix method

Dwight V. Sukup
Journal: The Leading Edge
Published: 01 August 2002
The Leading Edge (2002) 21 (8): 791–794.
DOI: https://doi.org/10.1190/1.1503189
... conventional streamer acquisition equipment but results in a set of large 3D field records acquired on a uniform rectangular grid and whose source positions are also on a regular grid. To accomplish this, a helix method will be applied to marine acquisition. Helix methods have been used by the Stanford...
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Journal Article

The double helix meets the crystal lattice; the power and pitfalls of nucleic acid approaches for biomineralogical investigations

Patricia Lynne Siering
Published: 01 December 1998
American Mineralogist (1998) 83 (11-12_Part_2): 1593–1607.
DOI: https://doi.org/10.2138/am-1998-11-1247
View PDF for article title, The double <span class="search-highlight">helix</span> meets the crystal lattice; the power and pitfalls of nucleic acid approaches for biomineralogical investigations
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Journal Article

Multidimensional recursive filters via a helix

Jon Claerbout
Journal: Geophysics
Published: 01 October 1998
Geophysics (1998) 63 (5): 1532–1541.
DOI: https://doi.org/10.1190/1.1444449
...Jon Claerbout Abstract Wind a wire onto a cylinder to create a helix. I show that a filter on the 1-D space of the wire mimics a 2-D filter on the cylindrical surface. Thus 2-D convolution can be done with a 1-D convolution program. I show some examples of 2-D recursive filtering (also called 2-D...
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Journal Article

Enumeration of 4-connected 3-dimensional nets and classification of framework silicates; III, Combination of helix, and zigzag, crankshaft and saw chains with simple 2D nets

J. V. Smith
Published: 01 June 1979
American Mineralogist (1979) 64 (5-6): 551–562.
...J. V. Smith Abstract Combination of a helix with the 3.6.3.6 2D net yields the quartz and NbO types of 3D nets. The latter cannot occur as the basis of a framework of linked tetrahedra. Combination of a helix with the 4 4 2D net yields the cristobalite net. Zigzag, crankshaft and saw chains yielded...
View PDF for article title, Enumeration of 4-connected 3-dimensional nets and classification of framework silicates; III, Combination of <span class="search-highlight">helix</span>, and zigzag, crankshaft and saw chains with simple 2D nets
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Journal Article

Innovative use of petrophysics in field rehabilitation, with examples from the Heather Field

Simon Kay, Steve Cuddy
Published: 01 December 2002
Petroleum Geoscience (2002) 8 (4): 317–325.
DOI: https://doi.org/10.1144/petgeo.8.4.317
... to acknowledge the contributions made by staff of Helix-RDS Limited and DNO Heather Limited. In appropriate circumstances, the FOIL function can be used for geosteering by determining the distance from the FWL. The method is applicable in horizontal wells where it is desirable to maintain a certain distance...
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Image
Schematic to show how the three polypeptide chains of the collagen macromolecule are wound in a coiled-coil helix. (a) Each polypeptide chain is composed of glycine, proline and hydroxyproline aminoacid residues (black spheres). The distance between adjacent residues is 3.1 Å. Each of the polypeptide chain is wound around its own long axis (“minor helix” axis) as a left-handed helix in a three-fold screw fashion, resulting in a primary repeat distance of 9.3 Å. Each chain is located at the vertex of an equilateral triangle and they are parallel; (b, c) The individual “minor helix” axes of the three chains are now coiled about the central axis (“major helix” axis) in a long right-handed helix; (d) This slightly distorts the distance between adjacent residues to 2.86 Å, yielding a repeat distance of the major helix axis to 28.6 Å, but gives rise to a very highly repetitive structure, sufficiently ordered to generate a wide angle X-ray diffraction pattern. [Reprinted with permission from Glimcher (1960). Copyright AAAS.]

Schematic to show how the three polypeptide chains of the collagen macromol...

Published: 01 January 2006
Figure 4. Schematic to show how the three polypeptide chains of the collagen macromolecule are wound in a coiled-coil helix. (a) Each polypeptide chain is composed of glycine, proline and hydroxyproline aminoacid residues (black spheres). The distance between adjacent residues is 3.1 Å. Each
Image
One period of a helix (radius r=1) oriented with its core along the x-axis: (a) y-z plane view and (b) x-z plane view.

One period of a helix (radius r = 1 ) oriented with its core along...

Published: 10 November 2020
Figure 2. One period of a helix (radius r = 1 ) oriented with its core along the x -axis: (a)  y - z plane view and (b)  x - z plane view.
Image
The helix transform. The gray-black “H”-shaped grid denotes a 2D filter, and the rectangle grid denotes the 2D seismic data. (a) Mapping a 2D filter onto the seismic data, (b) enclosing the seismic data into a cylinder with the end of the first column connected to the beginning of the second column, and (c) unwinding the seismic data into a series of numbers. (d) The same filter coefficients cover the same seismic data values if the 2D coils are expanded into 1D strings.

The helix transform. The gray-black “H”-shaped grid denotes a 2D filter, an...

Published: 22 November 2019
Figure 2. The helix transform. The gray-black “H”-shaped grid denotes a 2D filter, and the rectangle grid denotes the 2D seismic data. (a) Mapping a 2D filter onto the seismic data, (b) enclosing the seismic data into a cylinder with the end of the first column connected to the beginning
Image
Holocene species described in the Morsott region; (5) Helix chionodiscus (Pfeiffer, 1856); (6a–c) Rumina decollata (Linnæus, 1758); (7a, b) Sphincterochila candidissima (Draparnaud, 1801); (8) Cernuella globuloidea (Terver, 1839); (9) Coneuplecta confusa (Möllendorff, 1887); (10) Campylaea planospira (Lamarck, 1822); (11) Helicella stiparum (Rossmässler, 1854); (12) Zonitoides nitidus (Müller, 1774). 1 cm scale bar. Apex magnification 3 X. Global, apex, umbilical, and oral views of xerophilous and hygrophilous species.

Holocene species described in the Morsott region; (5) Helix chionodiscus ...

Published: 03 December 2018
Fig. 4 Holocene species described in the Morsott region; (5) Helix chionodiscus ( Pfeiffer, 1856 ); (6a–c) Rumina decollata ( Linnæus, 1758 ); (7a, b) Sphincterochila candidissima ( Draparnaud, 1801 ); (8) Cernuella globuloidea ( Terver, 1839 ); (9) Coneuplecta confusa ( Möllendorff
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Cross section through the Tunkillia prospect (after Helix Resources Annual Report 2003).

Cross section through the Tunkillia prospect (after Helix Resources Annual ...

Published: 01 December 2007
F ig . 3. Cross section through the Tunkillia prospect (after Helix Resources Annual Report 2003).
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The same data as in Figure 2 showing the helix derivative applied to the τ field used for flattening. A helix derivative behaves similarly to a gradient operator while being more isotropic. It enhances the identification of several channels which have been captured by the flattening process.

The same data as in Figure 2 showing the helix derivative applied to the ...

Published: 01 July 2007
Figure 4. The same data as in Figure 2 showing the helix derivative applied to the τ field used for flattening. A helix derivative behaves similarly to a gradient operator while being more isotropic. It enhances the identification of several channels which have been captured
Image
Schematic of the cone-helix model (modified after Double &amp; Hellawell 1974) for a cone with an apex angle α = 127° resulting from an overlap angle θ = 60° – 21.8° = 38.2°, illustrating a moiré pattern from the lattice coincidences between adjacent layers of graphene.

Schematic of the cone-helix model (modified after Double & Hellawell 1...

Published: 01 April 2007
F ig . 5. Schematic of the cone-helix model (modified after Double & Hellawell 1974 ) for a cone with an apex angle α = 127° resulting from an overlap angle θ = 60° – 21.8° = 38.2°, illustrating a moiré pattern from the lattice coincidences between adjacent layers of graphene.
Image
Filtering on a helix. The same filter coefficients overlie the same data values if the 2D coils are unwound into 1D strips. Figure courtesy of Sergey Fomel.

Filtering on a helix. The same filter coefficients overlie the same data va...

Published: 01 January 2004
Figure 14. Filtering on a helix. The same filter coefficients overlie the same data values if the 2D coils are unwound into 1D strips. Figure courtesy of Sergey Fomel.
Image
Estimated p with (a) the helix derivative (same as Figure 7b) and (b) the PEF. (c) Scaled version of (b) to increase the contrast inside the lake. The three plots are clipped to the 100th percentile. The term HC points to locations of higher contrast when the PEF is utilized for the inverse covariance operator. On the contrary, LF shows that the PEF slightly decreases the resolution (frequency content) of the final image by spreading information farther than the helix derivative.

Estimated p with (a) the helix derivative (same as Figure 7b ) and (b) t...

Published: 01 January 2004
Figure 10. Estimated p with (a) the helix derivative (same as Figure 7b ) and (b) the PEF. (c) Scaled version of (b) to increase the contrast inside the lake. The three plots are clipped to the 100th percentile. The term HC points to locations of higher contrast when the PEF is utilized
Image
Chromosomal DNA, DNA double helix, genes. The top part of this figure gives the basic “building blocks” of nucleic acids, i.e., the nucleotides, and their elementary components, the ribose (or deoxyribose) sugar units and purine/pyrimidine bases. The carbon numbering scheme for ribose and deoxyribose sugars is given as well. A simplified representation of double-stranded DNA(dsDNA) is likewise presented. Although not shown in this drawing, A–T base pairs form 2 hydrogen bonds, G–C base pairs form 3 hydrogen bonds, and the DNA helix itself exhibits a twisted helical structure. Lastly, chromosomes are DNA-protein complexes that are extremely condensed and supercoiled. The chromosome contains numerous genes, and if we were to magnify or enlarge a small region of the chromosome, we would observe that the chromosome is organized into chromatin and nucleosome DNA-protein superstructures. Such compact packing allows an incredible amount of genetic information to be stored in a very small volume within the nucleus.

Chromosomal DNA, DNA double helix, genes. The top part of this figure gives...

Published: 03 January 2003
Figure 2. Chromosomal DNA, DNA double helix, genes. The top part of this figure gives the basic “building blocks” of nucleic acids, i.e., the nucleotides, and their elementary components, the ribose (or deoxyribose) sugar units and purine/pyrimidine bases. The carbon numbering scheme for ribose
Image
Helix transform of 2D filters to one dimension (a scheme). The 2D filter (a) is equivalent to the 1D filter in (d), assuming that a shifted periodic condition is imposed on one of the axes (b and c.)

Helix transform of 2D filters to one dimension (a scheme). The 2D filter (a...

Published: 01 January 2003
F IG . 10. Helix transform of 2D filters to one dimension (a scheme). The 2D filter (a) is equivalent to the 1D filter in (d), assuming that a shifted periodic condition is imposed on one of the axes (b and c.)
Image
Illustration of 2D deconvolution with helix transform. The input is on the left: two spikes and two filters. The output of deconvolution is on the right.

Illustration of 2D deconvolution with helix transform. The input is on the ...

Published: 01 January 2003
F IG . 11. Illustration of 2D deconvolution with helix transform. The input is on the left: two spikes and two filters. The output of deconvolution is on the right.
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Example of four-vessel helix configuration.

Example of four-vessel helix configuration.

Published: 01 August 2002
Figure 3. Example of four-vessel helix configuration.
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Figure 7. Helix pomatia. The shell has been cut to allow the visualization of the columella (shell length = 40.73 mm). The coiling axis was calculated by the computing method based on five points of the suture of the teleoconch outline (solid circles).

Figure 7. Helix pomatia. The shell has been cut to allow the visualizati...

Published: 01 January 2000
Figure 7. Helix pomatia. The shell has been cut to allow the visualization of the columella (shell length = 40.73 mm). The coiling axis was calculated by the computing method based on five points of the suture of the teleoconch outline (solid circles).
Image
Holocene species described in the Morsott region; 0.5 mm and 1 cm scale bar; apex magnification 3 X; (1) Otala lactea (Müller, 1774); (2) Helix aperta (Born, 1778); (3) Helix melanostoma (Draparnaud, 1801); (4) Eobania Helix Vermiculata (Müller, 1774). The snails analyzed are intact, the morphological features of the xerophililous species found at Morsott are clear, turns, aperture, apex, columella siphon, these different photos show apex and oral views.

Holocene species described in the Morsott region; 0.5 mm and 1 cm scale bar...

Published: 03 December 2018
Fig. 3 Holocene species described in the Morsott region; 0.5 mm and 1 cm scale bar; apex magnification 3 X; (1) Otala lactea ( Müller, 1774 ); (2) Helix aperta ( Born, 1778 ); (3) Helix melanostoma ( Draparnaud, 1801 ); (4) Eobania Helix Vermiculata ( Müller, 1774 ). The snails analyzed