In situ measurements of reef squid polarization patterns using two-dimensional polarization data mapped onto three-dimensional tessellated surfaces.

Reef squids belong to a group reputed for polarization sensitivity, yet polarization patterns of reef squid have not been quantified in situ. To quantify polarization patterns from video polarimetric data, we developed a protocol to map two-dimensional polarization data onto squid-shaped three-dimensional tessellated surfaces. This protocol provided a robust data container used to investigate three-dimensional regions-of-interest, producing data lineouts derived from the squid's geometry. This protocol also extracted polarimeter and squid body orientations and the solar heading from polarization images. When averaged over the solar heading, the ventral midline gave a low degree of polarization (2.4 ± 5.3%), and the area between the ventral and flank midlines had higher values (9.0 ± 5.3%). These averaged data had a large discontinuity in the angle of polarization (AoP) at the mantle's ventral midline (64 ± 55°), with larger discontinuities measured on individual squid. Ray-tracing calculations demonstrated that the AoP pattern was not related to the squid's surface-normal geometry. However, the AoP followed virtual striation axes on the squid's surface oriented 24° to the squid's long axis, similar in angle (27°) to the striations of birefringent collagen fibres documented in other squid species' skin.

[Therapeutic dilemmas in the care of acetabular fractures]. / Terapijske dileme u zbrinjavanju prijeloma acetabuluma.

Breakages of acetabulum take special place in traumatism of pelvis luxation breakages of acetabulum are serious wound, which are followed by traumatic shock. Such wounds are hard medical-surgical problem what puts traumatology surgeon in dilemma how to look after the same. Etiologic fact of these breakages in 90% is direct or indirect accident trauma. In our work we demonstrate the mechanism of becoming of such breakage and after that we give classification of fracture and luxational-breakages of the acetabulum. The meaning of radiographically diagnostics in marking out fragments the place of the head of femur operating indication and with which approaching. The central place in the work takes empirical results of treating of 56 patients in the period of April 1975 to 31 st of March 1980 on Traumatological-orthopaedic Department to Common City Hospital in Skopje. The meaning of the surgeons about surgical treatment of breakage of acetabulum are still divided. We give algorithm of surgical treatment of breakage of acetaleulum. We present surgical approaching and surgical methods in those breakages. We'll explain three times meaning of biomechanical splint "Hornik" Dr Nikodinovski own model in postoperative treating so as in conservative treatment in luxational breakages of the acetabulum. Out attitudes are surgical reconstruction and fixation to young patients with early activating. We give rights double tractin to the old patients. We'll show post-traumatic and post surgical late sequelae of these breakages as they aseptical necrose of head of femur and coxatrose that go to 35%.