MORPHOMETRY OF LUMBAR INTERVERTEBRAL DISC WEDGE ANGLE, DISC HEIGHT AND CONCAVITY INDEX IN NORMAL SPINES

BACKGROUND: The lordotic wedging and height of the presacral disc avert detrimental loads and shearing of the lumbar spine. Age and functional degenerations affect these causing spinal disarrays frequently requiring lumbar reconstructive surgery. Reinstating the disc height and wedging to its optimum healthy state is essential for accomplished spinal rehabilitation. The fourth and fth lumbar segments being most predisposed to mechanical pathophysiology and surgical interventions were evaluated in a north-east Indian population. MATERIALS & METHOD: The disc wedge angle, vertebral and disc heights and concavity index were measured in eighty lumbar segments comprising of twenty males and twenty females. RESULTS: The disc-wedge angle, anterior, middle, posterior disc heights and concavity index were as follows: 12.06±1.67°, 12.27±1.25mm,10.83±1.04mm,6.95±0.77mm,0.90±0.01at L4/L5 and 15.65±1.83°, 15.15±1.67mm, 11.32±1.68mm, 6.79±0.79mm, 0.90±0.01 at L5/S1 in males and 13.02±1.66°, 13.03±1.30mm, 11.86±1.23mm, 6.44±0.95mm,0.90±0.01 at L4/L5 and 16.89±1.71°,36.40 ±1.29mm, 16.04± 1.62mm, 12.31± 1.77mm, 6.06±0.94mm and 0.088 ± 0.02 in females. CONCLUSION: The disc wedge angles and anterior and middle disc heights were signicantly higher in females while the vertebral and posterior disc heights and convexity index were larger in males. The larger lordotic wedging of L5/S1 intervertebral disc preserves the spinal conformation. All above dimensions decreased with age in both genders. Our study standardizes quantitative referral data for research, diagnosis and prothesis to resolve the existing discordances.

Growth and morphometric characteristics of the scallop Flexopecten glaber (Bivalvia: Pectinidae) reared in cages off the coast of Crimea (Black Sea)

The spat of the scallop Flexopecten glaber were collected in cages with the Pacific oyster Crassostrea gigas cultured on a mussel-and-oyster farm (outer roadstead of Sevastopol Bay). For two years they were reared in plastic cages at a depth of 2-3 m. The cages were periodically withdrawn to measure the size and weight parameters of the molluscs: the length (L, mm), height (H, mm), and width (D, mm) of shells and the total live weight (W, g). The correlations among the parameters under study are presented. The changes in the indices of the frontal (D/L) and sagittal (H/L) curvatures, convexity ((H+D)/L) and conditional volume (H×D×L/1000) of the shells in ontogenesis are shown. Upon reaching a shell length of 30-35 mm, the allometry of the volumetric and weight growth of molluscs changed from positive to negative. The largest values of the shell convexity index were registered in thesame length range. A conclusion about the interval-type growth of F. glaber in linear size and weight is made. It is suggested that the optimal strategy of shell formation in F. glaber in ontogenesis implies the ripening and the first reproduction of the molluscs occurring at the highest volumetric characteristics of the shell. The relationships for the linear size and weight growth ofF. glaber in the first two years of life are obtained. It is concluded that the scallop F. glaber should be considered as a possible element for the diversification of the existing aquaculture of molluscs (mussels and oysters) off the coast of Crimea.

Decomposition of 2D polygons and its effect in hydrological models

2D non-uniform polygonal meshes allow representation of the impact of landscape elements and small infrastructures on water flows. The initial vectorial mesh, derived from the intersection of several geographical information systems' layers, can have highly non-convex or sliver polygons. These bad-shaped elements compromise accurate numerical flow computation. We propose a flexible divide-and-conquer strategy to decompose polygons into physiographical meaningful parts using shape descriptors to better represent the surface terrain and hydrologic connectivity. We use the convexity index (CI) and the form factor (FF) to consider convex and square like optimum shapes. The strategy was applied to two peri-urban areas whose hydrologic response was simulated using distributed modeling. Good-quality meshes were generated with threshold values of CI≈0.8 and FF≈0.2, and CI≈0.95 and FF≈0.4 for undeveloped and highly urbanized zones, respectively. We concluded that the mesh segmentation facilitates the representation of the spatially distributed processes controlling not only the lumped response of the catchment, but also the spatial variability of water quantity and fluxes within it at medium and small scales.