Polygonal Contour Research Articles

TRAITEMENT AUTOMATIQUE DES SONDAGES ELECTRIQUES AUTOMATIC PROCESSING OF ELECTRICAL SOUNDINGS*

TRAITEMENT AUTOMATIQUE DES SONDAGES ELECTRIQUES AUTOMATIC PROCESSING OF ELECTRICAL SOUNDINGS*

A note on minimal length polygonal approximation to a digitized contour

A method for extracting a smooth polygonal contour from a digitized image is illustrated. The ordered sequence of contour points and the connection graph of the image are first obtained by a modified Ledley algorithm in one image scan. A minimal perimeter polygon subjected to specified constraints is then chosen as the approximating contour. The determination of the minimal polygon can be reduced to a nonlinear programming problem, solved by an algorithm which takes into account the weak bonds between variables. Some examples are presented, and the corresponding computing times are listed.

The transverse flexure of uniformly loaded curvilinear and rectilinear polygonal plates

AbstractComplex variable methods are applied to derive exact solutions in closed forms for the small deflexions of uniformly loaded thin isotropic plates bounded by regular curvilinear polygonal contours havingnsides. The supported boundary is either clamped or has equal boundary cross-couples. For rectilinear edges the latter conditions agree with those for a simply supported boundary. The plates taken in thez-plane are conformally mapped on the unit circle in the ζ-plane by the general mapping function

A virus disease of the Indian rhinoceros beetle, Oryctes rhinoceros (linnaeus), caused by a new type of insect virus, Rhabdionvirus oryctes gen. n., sp. n

During investigations on the pathology of field populations of Oryctes rhinoceros (Linnaeus) in Southeast Asia and in certain islands of the South Pacific, grubs suffering from a virus disease were detected in Malaya. Signs and symptoms of this so-called “Malaya disease” are described. In diseased larvae, the fat body is greatly disintegrated. Fat cells often show a striking proliferative response to virus infection. By differential centrifugation of suspensions of homogenized affected fat-body lobes, spherical viral particles with mostly polygonal contours and an average diameter of 164 ± 16 mμ could be isolated together with a comparatively low number of virus rods measuring about 200 × 70 mμ. These viral sediments proved highly infective for larvae when inoculated into the body cavity. The same was the case with filtrates of homogenized fat body of diseased larvae when filters with a mean pore size of 1 micron, 600 mμ, and 300 mμ were used. Injection of filtrates passed through 100-mμ-pore filters had no apparent effect on the larvae, yet the emerging adults were crippled. Ultrathin sections revealed that the nuclei of fat-body cells are the principal sites of virus reproduction, yet repeatedly virogenic foci could also be observed in the cytoplasm. In an advanced stage of cell infection the hypertrophied nuclei contain crowds of singleor double-membraned spherical viral particles (shells), most of them ranging in diameter from 120 to 230 mμ (mean 160 mμ), and, closely associated with them, masses of virus rods with a length predominantly ranging from 170 to 210 mμ (mean 195 mμ) and an average width of 70 mμ. Both components are identical with the isolated spheres and rods. The virus rods, being the mature form of the virus, have a highly differentiated structure. They are established (1) from dense, chromatinlike virogenic stroma, (2) from loose, fibrillar and granular stromal material, (3) from filaments, and (4) from inside of the single- or double-membraned spherical particles (shells). Thus, the spheres represent viral developmental stages. The virus rods are not occluded in polyhedra or capsules of microcrystalline proteinaceous material. Yet clusters of rods may be densely packed in a two- or three-dimensional pseudocrystalline pattern. The disease is easily transmissible to third-instar larvae by contaminated food as well as by intrahemocoelic inoculation. The period of lethal infection is from about 6 to 30 days. Peroral and intrahemocoelic transmission of the disease to larvae of Oryctes nasicornis (Linnaeus) also is easily effected. The virus cannot be classed with any known group of insect viruses. Accordingly, it is placed in a new genus for which the generic name Rhabdionvirus gen.n. is proposed. The type species of this new genus (the virus under discussion) is named Rhabdionvirus oryctes gen. n., sp. n.

EFFECT OF ENTRANCE ON SEICHE MOTION IN OCEAN PORTS

The seiche motion induced in a partially open harbour is uniquely determined by the standing wave pattern formed in the outside ocean. The variable location and size of the coupling makes the problem essentially three-dimensional. Existing potential theory has been extended, for the case of a simple rectangular port, to simulate ocean conditions by approximating the open ocean by another rectangular basin of large size. The theoretical problem then reduces to solving the Neunan problem for the two-dimensional Helmholtz equation V*F + K*F m o for a polygonal contour. The finite dimensional approximation of an infinite domain is, however, unsatisfactory at least from the analytical point of view.
 This difficulty has been removed, in this paper, by using elliptic-cylindrical co-ordinates for the semi-infinite domain in which the perturbation potential has been expanded in terms periodic Mathieu functions. These theoretical developments have been verified by a series of numerical calculations and experimental studies.

Bending of Curvilinear and Rectilinear Polygonal Plates Symmetrically Loaded Over a Concentric Circle

ABSTRACTComplex variable methods are applied to obtain exact solutions for the complex potentials and deflexions of thin isotropic slabs bounded by regular curvilinear polygonal contours withnsides and subject to symmetrical loading distributed over a concentric circle. The supported boundary is either clamped or has equal boundary cross-couples. The plates taken in thez-plane are conformally mapped on the unit circle in the ζ-plane by the mapping function. Polynomial approximations to the Schwarz—Christoffel transformations are then used to discuss the bending of clamped and simply supported rectilinear plates symmetrically loaded over a concentric circle or acted upon by a central point load.

Changes in Cells of Adenohypophysis of Male Rats with Castration and Testosterone Administration

Twenty-seven castrated male adult rats of Wistar strain were devided into three experimental groups: The 1st group is non-treated with post-puberal gonadectomy as the control, the 2nd is repeatedly given testosterone propionate (T. P.) 0.05mg/day immediately after the operation, and the 3rd is repeatedly given T. P. 0.5mg/day in the same way. All experimental animals with or without the prolonged administration of the hormones were decapitated respectively 2, 6 and 10 weeks after the castration. The cytological observations obtained in the cells of adenohypohysis were as follows:Two weeks after the castration, most of β-cells became larger and spherical (gonadotroph), but slender polygonal β-cells (thyrotroph) frequently occurring in intact animals were reduced in number by the removal. Two kinds of β-cells were together strongly stained in general with periodic acid SCHIFF's reaction (PAS). The former is scattered at the whole area of adenohypophysis, and especially accumulated at the vicinity of pars intermedia (sex zone) and the center of the anterior lobe. The signet ring possibly identified to the negative shadow of GOIGI apparatus increased in number and diameter in gonadotrophs. Within 6 weeks, there appeared a great majority of swelling gonadotrophs containing a large size of signetring. Huge colloid substance occupping the cell-body was often recognized in some of large gonadotrophs. Such a kind of β-cell including many tiny vacuoles looks to be rather akin to a degenerating cell. Within the lapse of 10 weeks the whole area of adenohypophysis was full of large spherical gonadotrophs in which expanded signet-ring is usually situated. They may correspond to so-called castration cell of MAXIMOW. α-cells atrophied in 2 weeks, but conversely enlarged in 6 weeks and recovered to the normal level in 10 weeks. The steps in transformation of γ-cells into β-cells were detectable with facility all through the periods following the castration.In spite of the administratin of T. P. 0.05mg/day to the castrated rats, gonadotrophs were not altered in their frequency in 2 weeks; most of them constantly enclosed signet-ring and were stained with PAS, resembling the castration cells, while thyrotrophs stained strongly with PAS began to appear abundantly. By the prolonged administration for 6 weeks, gnoadotrophs diminished apparently in number and fell into a hyperchromatic degeneration, leaving the atrophic signet-ring within the cell-body, they were, therefore, no longer entitled to the castration cells. Further the number of gonadotrophs was reduced profoundly in 10 weeks, whose signet-ring showed the reduction in diameter, despite their reacting ability with PAS was not so much alleviative. The alterations in α-cells induced by the castration resulted in the restoration by the hormone therapy. The changes in α-cells are equivalent in general to those in castrated rats.In rats with the persistent injection of 0.5mg/day T. P., most of β-cells atrophied exceedingly even in 2 weeks; they were strongly stained with PAS and provided the condensed homogeneous cytoplasm sometimes containing a small size of signet-ring. Thus the injection of higher dose of hormone made not only the atrophic pattern, but also remarkable reduction in number of β-cells. Evidences were present that gonadotrophs produced an improvement of pathological hyperactivity induced by the castration, and moreover attained to status of hypoactivity. α-cells increased in number and were recoved from the diminution following the castration. Within 6 weeks all of β-cells fell into outstanding atrophy and have slender polygonal contour without an exception; large spherical gonadotrophs completely disappeared in remaining a few withering thyrotroph at the center of the adenohypophysis. However, atrophic changes were much or less alleviated in 10 weeks

Histological studies on the islets of Langerhans in normal rabbits and rats and those treated with sulfonamide derivatives.

Three normal control and 9 treated male adult rabbits and 10 control and 18 treated male adult rats were used for the experiment. In rabbits, 0.25, 0.5 and 1. 0g of IPTD, 0.5, 1.0 and 2.0g of BZ-55 and 2.0g of D-860 were injected intravenously per kg of body weight as well as 1.0 and 2.0g of D-860 intramuscularly. In rats, 0.25, 0.5 and 1.0g of IPTD, 0.5, 1.0 and 2.0g of BZ-55 and 0.5, 1.0 and 2.0g of D-860 were given intraperitoneally per kg of body weight. The blood sugar value was determined by Somogyi-Nelson's method before and at an hour interval up to 6hrs. after injection in rabbits. The value reached to minimum in 2 to 4hrs. in both rabbits and rats, the decrease being in general proportional with the dosage.In control rabbits alpha cells with clear polygonal contours were scattered either in the periphery or the central area of the islets and stained diffusely with phloxin of Gomori's CHP method. It was observed that alpha cells contain a small amount of Mt in the cell bodies. In rats, it was found the alpha cell zone formed a sort of syncytium on the periphery of the islets surrounding the central area. They were rich nuclei and in rod shaped structures and P-positive. Beta cells having in general clear boundaries were packed with rod shaped structures (CH-positive) and mitochondria or fine granules. Beta granules were not coarse but very fine. The rod shaped structure or mitochondria could be differentiated in beta cells in such a way that they were in close correlation each other, though it was not clear to which beta granules corresponded.It was observed that the administration of sulfonamide derivatives (5) reduced as a rule the number of alpha cells, changing the degree with islet or animal. No degenerative and destructive alpha cells could be observed. On the other hand, with any dosage of S the CH-positive rod-shaped structures or Mt were observed near the sinusoidal wall when the blood sugar reached the lowest value. It can be therefore considered that these histological changes can be interpreted as the results of release of the hormone caused by stimulation of secretory activity in the cells by the administration of S.In the islets of Langerhans in the pancreas of rabbits and rats the transition from alpha cell to beta cell can be observed even in the normal state. However, with the administration of S the speed of transition seems to be accelerated and the number of beta cells was considerably increased. With the dose of 2.0g/kg, beta cells were increased quantitatively and a cluster of nuclei appeared. The appearance of vacuoles was also observed in the cell bodies.