scholarly journals Binary Space Partitions for Axis-Parallel Segments, Rectangles, and Hyperrectangles

2004 ◽  
Vol 31 (2) ◽  
pp. 207-227 ◽  
Author(s):  
Adrian Dumitrescu ◽  
Joseph S. B. Mitchell ◽  
Micha Sharir
Keyword(s):  
Axis Parallel

The limits of strain and lattice parameter measurements by CBED

1989 ◽  
Vol 47 ◽  
pp. 518-519
Author(s):  
Hamish L. Fraser
Keyword(s):  
Electron Beam ◽  
Mirror Symmetry ◽  
Local Symmetry ◽  
Lattice Parameter ◽  
Growth Direction ◽  
Surface Relaxation ◽  
Strained Layer ◽  
Axis Parallel ◽  
Local Lattice ◽  
Strained Layer Superlattice

The topic of strain and lattice parameter measurements using CBED is discussed by reference to several examples. In this paper, only one of these examples is referenced because of the limitation of length. In this technique, scattering in the higher order Laue zones is used to determine local lattice parameters. Work (e.g. 1) has concentrated on a model strained-layer superlattice, namely Si/Gex-Si1-x. In bulk samples, the strain is expected to be tetragonal in nature with the unique axis parallel to [100], the growth direction. When CBED patterns are recorded from the alloy epi-layers, the symmetries exhibited by the patterns are not tetragonal, but are in fact distorted from this to lower symmetries. The spatial variation of the distortion close to a strained-layer interface has been assessed. This is most readily noted by consideration of Fig. 1(a-c), which show enlargements of CBED patterns for various locations and compositions of Ge. Thus, Fig. 1(a) was obtained with the electron beam positioned in the center of a 5Ge epilayer and the distortion is consistent with an orthorhombic distortion. When the beam is situated at about 150 nm from the interface, the same part of the CBED pattern is shown in Fig. 1(b); clearly, the symmetry exhibited by the mirror planes in Fig. 1 is broken. Finally, when the electron beam is positioned in the center of a 10Ge epilayer, the CBED pattern yields the result shown in Fig. 1(c). In this case, the break in the mirror symmetry is independent of distance form the heterointerface, as might be expected from the increase in the mismatch between 5 and 10%Ge, i.e. 0.2 to 0.4%, respectively. From computer simulation, Fig.2, the apparent monocline distortion corresponding to the 5Ge epilayer is quantified as a100 = 0.5443 nm, a010 = 0.5429 nm and a001 = 0.5440 nm (all ± 0.0001 nm), and α = β = 90°, γ = 89.96 ± 0.02°. These local symmetry changes are most likely due to surface relaxation phenomena.

Occurrence and Development of a Dorsal Gland in the Leaves of Twelve Cultivars of Ficus benjamina L. (Weeping Fig)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 537b-537
Author(s):  
Svoboda V. Pennisi ◽  
Dennis B. McConnell ◽  
Richard W. Henley
Keyword(s):  
Leaf Size ◽  
Dark Spot ◽  
Ficus Benjamina ◽  
Axis Parallel ◽  
Glandular Cells ◽  
Phenolic Substances ◽  
Dark Color ◽  
Columnar Cells ◽  
Dorsal Gland ◽  
Colorimetric Reaction

Ficus benjamina plants are an integral part of most modern interior landscapes. Reports from growers and interiorscape managers have drawn attention to a specific problem related to large F. benjamina plants, namely the occurrence of a dark oval spot on the abaxial surface of the leaf base. Twelve cultivars of F. benjamina were examined: Christine, Citation, Florida Spire, Kelly, Kiki, Midnight, Monique, Stacey, Wintergreen, Dwarf Nikita, Spearmint, and Starlight. Anatomically, the dorsal gland consisted of one to several layers of densely stained, columnar cells. Positive colorimetric reaction for phenolics was obtained in the glandular cells. Developmentally, the gland cells could not be distinguished from the regular epidermal cells until ≈30% of final leaf size was reached. The cells of the outermost glandular layer changed shape from rectangular with long axis parallel to the leaf surface to elongate with long axis perpendicular to the surface. In a mature leaf, the thickness of the glandular layer was between 20 and 30 μm. Externally, at this stage, no dark spot, indicative of the gland's location, could be observed. In older leaves, however, an accumulation of phenolic substances led to appearance of dorsal dark spot. All cultivars possessed glandular layer. However, this area did not darken in all cultivars; Christine, Citation, Florida Spire, Kelly, Kiki, and Stacey developed small dark spots, while Dwarf Nikita and Starlight had numerous, well-pronounced glandular regions. This study showed that the dark spots in F. benjamina cultivars were a normal morphological feature. Although the gland was present in every cultivar, only a few cultivars developed a dark color.

scholarly journals Turán-type results for intersection graphs of boxes

2021 ◽  
pp. 1-6
Author(s):  
István Tomon ◽  
Dmitriy Zakharov
Keyword(s):  
Short Note ◽  
Intersection Graph ◽  
Intersection Graphs ◽  
Poset Dimension ◽  
Axis Parallel ◽  
Turán Theorem ◽  
Separation Dimension

Abstract In this short note, we prove the following analog of the Kővári–Sós–Turán theorem for intersection graphs of boxes. If G is the intersection graph of n axis-parallel boxes in $${{\mathbb{R}}^d}$$ such that G contains no copy of K t,t , then G has at most ctn( log n)2d+3 edges, where c = c(d)>0 only depends on d. Our proof is based on exploring connections between boxicity, separation dimension and poset dimension. Using this approach, we also show that a construction of Basit, Chernikov, Starchenko, Tao and Tran of K2,2-free incidence graphs of points and rectangles in the plane can be used to disprove a conjecture of Alon, Basavaraju, Chandran, Mathew and Rajendraprasad. We show that there exist graphs of separation dimension 4 having superlinear number of edges.

scholarly journals Influence of Anatomical Parameters on the Dimensions of the Subantral Space and Sinus Mucosa Thickening after Sinus Floor Elevation. A Retrospective Cone Beam Computed Tomography Study

2021 ◽  
Vol 9 (7) ◽  
pp. 76
Author(s):  
Yuki Omori ◽  
Yasushi Nakajima ◽  
Hideki Imai ◽  
Daichi Yonezawa ◽  
Mauro Ferri ◽  
...  
Keyword(s):  
Cone Beam ◽  
Sinus Floor Elevation ◽  
Axis Parallel ◽  
Height Gain ◽  
Maxillary Sinus Floor ◽  
Sinus Floor ◽  
Maxillary Sinus Floor Elevation ◽  
Sinus Mucosa ◽  
Anatomical Parameters ◽  
Maxillary Sinuses

Background: Various anatomical parameters might influence the surgical approach for maxillary sinus floor elevation. The objective of the present study was to retrospectively evaluate the influence of anatomical parameters on the dimensions of the subantral space and of the sinus mucosa thickening after sinus floor elevation. Material and Methods: Seventy-eight maxillary sinuses in sixty-five patients were evaluated on cone beam computed tomographies taken before surgery and after one week (t1w) and nine months (t9m). Several parameters such as the distance XF between an axis parallel to the base of the nose (X-axes) and the sinus floor (F) were correlated with the height gain (IF) at t1w and t9m and the post-surgical edema. Results: A weak significant positive correlation was observed between height gain vs. sinus height of interest (XF), the balcony, and the sinus floor angle. The post-surgical edema was influenced by the initial mucosa thickness and the xenograft used. Conclusions: Various parameters might affect height gain and sinus mucosa thickening after sinus floor elevation. The height of interest, the balcony, and the sinus floor angle showed significant correlations with height gain. The initial thickness of the mucosa and the biomaterial used influenced the post-surgical edema.

A Krasnosel’skii-type theorem for certain orthogonal polytopes starshaped via k-staircase paths

2020 ◽  
Vol 20 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Marilyn Breen
Keyword(s):  
Type Theorem ◽  
Common Point ◽  
Finite Family ◽  
Intersection Graph ◽  
Axis Parallel ◽  
Orthogonal Polytopes

AbstractLet 𝒞 be a finite family of distinct axis-parallel boxes in ℝd whose intersection graph is a tree, and let S = ⋃{C : C in 𝒞}. If every two points of S see a common point of S via k-staircase paths, then S is starshaped via k-staircase paths. Moreover, the k-staircase kernel of S will be convex via k-staircases.

Glossifungites gingrasi n. isp., a probable subaqueous insect domicile from the Cretaceous Ferron Sandstone, Utah

2021 ◽  
pp. 1-13
Author(s):  
M. Ryan King ◽  
Andrew D. La Croix ◽  
Terry A. Gates ◽  
Paul B. Anderson ◽  
Lindsay E. Zanno
Keyword(s):  
Coastal Plain ◽  
Upper Cretaceous ◽  
Filter Feeding ◽  
Chironomid Larvae ◽  
Large Size ◽  
Rock Record ◽  
Axis Parallel ◽  
Freshwater Fauna

Abstract A new ichnospecies, Glossifungites gingrasi n. isp., is described from multiple locations in basal sand-filled coastal plain distributary channels of the Turonian (Upper Cretaceous) Ferron Sandstone (central Utah). Glossifungites gingrasi n. isp. is attributed to the ichnogenus Glossifungites based on the presence of scratch imprints, passive fill, and a tongue-shaped structure, yet the new ichnospecies is distinct because it displays transverse bioglyphs that run perpendicular to the planiform structure, which contrasts to the axis parallel bioglyphs present in the ichnospecies G. saxicava. The transverse arrangement of ornamentation exhibited by G. gingrasi n. isp. is observed in modern subaqueous insect burrows produced by mayfly and chironomid larvae, and constitutes a way to differentiate insect-generated burrows from structures produced by crustaceans that are known to create other Glossifungites ichnospecies. Differentiating insect- from crustacean-generated burrows is significant because it provides a way to distinguish bioturbation by marine-recruited fauna from that produced by freshwater fauna in the rock record, making G. gingrasi n. isp. a valuable ichnological tool for paleoenvironmental and stratigraphic interpretation. While G. gingrasi n. isp. may represent a burrow created by a variety of filter-feeding subaqueous insects, the large size of G. gingrasi n. isp. in the Ferron Sandstone suggests that the largest specimens are probable mayfly burrows and supports the assertion that burrowing mayflies (e.g., Polymitarcyidae and Ephemeridae) adapted to domicile filter-feeding during or prior to the Turonian. UUID: http://zoobank.org/a033b22f-bf09-481a-975e-3a1b096154cc

scholarly journals Crystal structures and conformations of two Diels–Alder adduct derivatives: 1,8-bis(thiophen-2-yl)-14-oxatetracyclo[6.5.1.02,7.09,13]tetradeca-2(7),3,5-trien-10-one and 1,8-diphenyl-14-oxatetracyclo[6.5.1.02,7.09,13] tetradeca-2,4,6-trien-10-one

2015 ◽  
Vol 71 (2) ◽  
pp. 213-216
Author(s):  
S. Gopinath ◽  
P. Narayanan ◽  
K. Sethusankar ◽  
Meganathan Nandakumar ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Crystal Packing ◽  
Rotation Axis ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Compound I ◽  
Diels Alder Reaction ◽  
Phenyl Rings ◽  
Axis Parallel ◽  
Alder Adduct

The title compounds, C21H16O2S2(I) and C25H20O2(II), are products of a tandem `pincer' Diels–Alder reaction consisting of [2 + 2] cycloadditions between benzo[c]furan and cyclopentanone. Each comprises a fused tetracyclic ring system containing two five-membered rings (inenvelopeconformations with the O atom as the flap) and six-membered rings (inboatconformations). In addition, two thiophene rings in (I) and two phenyl rings in (II) are attached to the tetracyclic ring system. The cyclopentanone ring adopts atwistedconformation in (I) and anenvelopeconformation in (II). In (I), the thiophene rings are positionally disordered over two sets of sites, with occupancy ratios of 0.901 (2):0.099 (2) and 0.666 (2):0.334 (2). In (II), the oxygen atom of the cyclopentanone ring is rotationally disordered over two sites with an occupancy ratio of 0.579 (4):0.421 (4). The molecular structure of (I) is stabilized by an intramolecular C—H...O hydrogen bond, which generates anS(7) ring motif. In the crystal, the molecules are linkedviaweak C—H...O hydrogen bonds, which generateR22(16) ring motifs in (I) andC(8) chains in (II). In both structures, the crystal packing also features C—H...π interactions. The crystal studied of compound (I) was twinned by non-merohedry. The twin component is related by the twin law [−1 0 0 −0.101 1 −0.484 0 0 −1] operated by a twofold rotation axis parallel to thebaxis. The structure of (I) was refined with a twin scale factor of 0.275 (2).

Functional simulator of 3-axis parallel kinematic milling machine

2008 ◽  
Vol 42 (7-8) ◽  
pp. 813-821 ◽  
Author(s):  
Milos Glavonjic ◽  
Dragan Milutinovic ◽  
Sasa Zivanovic
Keyword(s):  
Milling Machine ◽  
Axis Parallel ◽  
Parallel Kinematic

A characteristic type of instability in the large deflexions of elastic plates III. Curved rectangular plates in axial compression

1954 ◽  
Vol 222 (1148) ◽  
pp. 44-59 ◽  
Keyword(s):  
Axial Compression ◽  
Rectangular Plates ◽  
Bending Moments ◽  
Elastic Plates ◽  
Characteristic Type ◽  
Circular Tubes ◽  
Axis Parallel ◽  
Post Buckling ◽  
Thin Walled ◽  
The Stability

The analysis of part I is extended to deal with the case of free-edged rectangular plates having an initial curvature about an axis parallel to one pair of opposite edges and loaded by distributed bending moments applied to the straight edges and compressive forces applied to the curved edges. In particular, the stability and post-buckling behaviour of such plates subjected to the compressive forces alone is studied. The axially symmetrical buckling of thin-walled circular tubes in axial compression is also considered. Experimental plates are found to buckle at loads rather lower than those predicted.

Sign in / Sign up

Export Citation Format

Share Document