Degree Of Variation In Shape Research Articles

Metastatic Blue Nevus-Like Melanoma Detected by Liquid-Based Catheterized Urine Cytology

Primary or metastatic malignant melanoma can mimic benign blue nevus in rare cases, making the diagnosis challenging. Herein, we report an exceptionally rare case of blue nevus-like melanoma and its blue nevus-like metastasis which was detected by catheterized urine cytology. The patient presented with blue-colored papuloplaques on his temple which were diagnosed as blue nevus-like melanoma on punch biopsies. While he was admitted for administration of chemotherapy, hematuria was detected. Catheterized urine cytology revealed singly scattered oval to spindle-shaped pigmented cells with a moderate degree of variation in shape and size. Many of them had small nuclei with indiscernible to inconspicuous nucleoli while only a few cells showed nuclear enlargement and nuclear hyperchromasia, which could be diagnostic pitfalls. Most of the cells on the smear were positive for HMB45 immunostaining, which confirmed the diagnosis of metastatic blue nevus-like melanoma. To the best of our knowledge, the present case is the first report describing cytomorphologic findings of blue nevus-like metastasis of melanoma in the urine specimen.

Size and shape variation in Australopithecus afarensis proximal femora

The degree of size and shape variation in the A. afarensis fossil sample has been interpreted in a variety of ways. Size variation has been described as exceeding that of extant hominoids, similar to that of strongly sexually dimorphic hominoids, and best matched to modern humans. The degree of shape variation has been characterized both as great and negligible. Recent fieldwork has increased the proximal femoral sample, providing new data with which to examine variation. The proximal femur of A. afarensis is analyzed in a comparative framework in order to gauge the magnitude of size and shape variation in this element. Seven of the best-preserved A. afarensis proximal femora contribute to the analysis (A.L. 128-1, A.L. 152-2, A.L. 211-1, A.L. 288-1ap, A.L. 333-3, A.L. 333-123, A.L. 827-1). Comparative samples from Pan, Pongo, Gorilla, and Homo provide context for interpreting variation among the fossils. The coefficient of variation (CV) of linear measurements is used to estimate size variation. Bootstrap resampling of CVs from extant hominoids provides distributions for comparison to A. afarensis CVs. Ratios of linear measurements provide scale-free shape variables that are used in pairwise comparisons. The Euclidean distance between pairs of A. afarensis are compared to the Euclidean distances between extant hominoid pairs. As found in some earlier analyses, size variation in A. afarensis is accommodated best in gorillas and orangutans. The magnitude of difference in shape between A. afarensis pairs is exceeded by most taxa, indicating that shape variation is not extreme. These general findings are contradicted by a few instances of excessive size and shape variation. These are uncharacteristic results and could point to temporal bias, although other alternatives are explored. The signal from the proximal femur is that size variation in A. afarensis is like that of the strongly sexually dimorphic apes, and shape variation is well within the range of most hominoids irrespective of their degree of size dimorphism.

Natural occurrence of entomophthoralean fungi pathogenic to collembolans.

The aim of this study was to assess the natural occurrence of fungi from the order Entomophthorales (Zygomycetes) pathogenic to a range of collembolan species. A total of 11,709 collembolans representing a total of 15 species from all three subclasses within Collembola were collected and incubated. Infection with Neozygites-like spp. (Entomophthorales) was recorded in the two subclasses, Arthropleona and Symphypleona. The morphology of the primary conidia of the Neozygites-like fungi infecting collembolans showed a high degree of variation in shape and size, and the fungi were divisible into five groups. One group consisted of Neozygites sminthuri, while the other four groups, while still closely resembling the genus Neozygites, did not fit within the description of any known species and were preliminarily designated Neozygites sp. nov. 1 to 4. Neozygites sp. nov. 1, infecting Sphaeridia pumilis, was observed to form globular secondary conidia, which have not been observed before within the genus Neozygites. A formal species description needs, however, yet to be performed. The infection was mainly found in species from the subclass Symphypleona, where two new host genera for Neozygites, Deuterosminthurus and Sphaeridia, were recorded. However, the prevalence of Neozygites spp. was low, up to 10% in S. pumilis, 6% in Sminthurus viridis, and below 1% in Deuterosminthurus sulphureus. Infection with an obligatory entomopathogenic fungus was for the first time well documented within the subclass Arthropleona, where specimens of Orchesella cincta and Orchesella villosa sporulated with a N. sminthuri-like fungus. Additionally, infection with the facultative pathogen Conidiobolus coronatus was recorded from several hosts representing both the subclass Arthropleona (Isotoma anglicana and O. cincta) and the subclass Symphypleona (Dicyrtoma sp. and S. viridis). For most species the prevalence of C. coronatus resembled that of Neozygites spp. and did not exceed 8.8%. The only exception was Dicyrtoma sp., for which the only associated entomophthoralean fungus was C. coronatus, where the prevalence reached 17.8% infection.

Second metacarpal cross-sectional geometry: Rehabilitating a circular argument.

Radiogrammetry of the second metacarpal has long served as a measure of normal and abnormal bone growth and aging, functional asymmetry, and fracture risk in osteoporosis. The method relies on algebraic interpretation (circular or elliptical models) of uni- or biplanar radiographic images. This paper tests the conformance of these models with actual measures of metacarpal geometric variation in a sample of 356 bones from an historic archaeological sample. Both the circular and elliptical models significantly over-estimate actual values for all variables (e.g., total area (3.05% and 9.42%, respectively) and cortical area (7.25% and 12.25%), bending rigidity about the mediolateral (13.88% and 20.92%) and anteroposterior axes (17.35% for the elliptical model). The greater degree of systematic bias found for the elliptical model is contrary to results of an earlier study (Lazenby, 1997), and suggests that sample composition can influence the method error associated with a particular approach. The import of radiogrammetric bias will depend on the degree of shape variation among samples compared (e.g., left vs right, male vs female, etc.), which in most cases cannot be predetermined. Consequently, reduced major axis equations were derived from regressing actual on estimated values for total area (TA), cortical area (CA) and two measures of bending rigidity (Ix, Iy) in order to permit adjustment for radiogrammetric error associated with these algebraic models. Application of these formulae to a hold-out sample showed no significant differences between actual and predicted values. Am. J. Hum. Biol. 10:747-756, 1998. © 1998 Wiley-Liss, Inc.

Classification of multilayered folds based on harmonic analysis: example from central India

The harmony of multilayered folds can be determined objectively by comparing the b3/b1 (ratio of third and first coefficient of harmonic components of the Fourier series) for different surfaces in an individual fold. A plot of the b3/b1 value against surface number provides a simple graphical technique for assessing fold harmony. On such a diagram, a straight line parallel to abscissa denotes a strictly harmonic fold, while other lines and curves denote variation of fold shape from surface to surface. A new scheme of multilayered fold classification based on ‘Index of Non-Harmony (INH)’, which reveals the degree of variation in shape of different surfaces of the fold, is proposed. INH is obtained from standard deviation (σn) of b3/b1 ratios of ‘n’ number of surfaces of a quarter wave sector. On the basis of values of INH ( = 1000 · σn) the multilayered folds are classified as ‘Strictly Harmonic’ (INH = 0), ‘Periharmonic’ (0 < INH ≤ 15), ‘Subharmonic’ (15 < INH ≤ 30), ‘Subnonharmonic’ (30 < INH ≤ 45), ‘Nonharmonic’ (45 < INH ≤ 75) and ‘Strongly Nonharmonic’ (INH > 75). In a case study of polydeformed Precambrian rocks of central India, it is found that the index of nonharmony decreases in folds of later (younger) generations.

Deformations, isosymmetric manifolds, and higher dimensional form space symmetries for point ensembles (polygonal forms) under O(2) symmetry III. Motifs in geometric figures and constraints in form spaces

A polygonal form F specified by a set of N points in E n (here: a plane) can be represented by a point in an n · N -dimensional form space F . A motif M within such a form has been defined as a subset M ⊆ F on which certain constraints are imposed. Different types of constraints are discussed. In any case, every independent constraint reduces the dimension of the form space by one so that the resulting forms correspond to points in a constrained form space F c ⊂ F . The subspaces F c are investigated for some forms containing rigid and—as a novel aspect— deformable motifs, and they are correlated with the full form spaces F described in previous papers [1–3]. Furthermore, constraints which do not lead to motifs are treated. Generally, constraints of distances define circles in certain planes of F so that angular coordinates have to be used. As a special case, cyclic polygons have been found to lie on hyperspheres in F . On the other hand, if the distances between points are constrained to such an extent that only two degrees of freedom (the global rotation and one degree of shape variation) are left, then the resulting forms have been found to lie on hyperellipsoids in F . These constitute special cases of isodiastemic manifolds consisting of forms with fixed point distances.