Distribution and reproductive biology of Sepietta neglecta (Naef, 1916)(Cephalopoda: Sepioidea) in the North Aegean Sea (Eastern Mediterranean)

Sepietta neglecta (Naef, 1916) is the most rarely caught species of the genus Sepietta (Sepiolidae). Its presence in the North Aegean Sea (Eastern Mediterranean) is recorded for the first time, on the basis of 56 specimens, collected at depths from 24 to 262 m, during six seasonal trawl surveys carried out from September 1992 to December 1992. Specimens were dissected, weighed, and assigned a maturity stage. The weight-length relationship was found to be allometric. Mature individuals were caught during all six cruises. In mature males, from 150 to 240 spermatophores were counted, whereas in females, up to 127 oocytes were counted of which only a fraction (6-36%) were in the last stage of development. The ovaries of mature females contained oocytes at three vitellogenetic stages: primary oogonia, maturing oocytes, and smooth ripe oocytes ready to be released. The diameter of ripe occytes, in the major axis, ranged from 1.4 to 2.8 mm

Age determination and growth of leaping mullet, (Liza saliens R.1810) from the Messolonghi Etoliko lagoon (western Greece)

This study is the first detailed work on the age and growth of the leaping mullet (Liza saliens, Risso 1810) in the central Mediterranean. During the period 1991-1995 the age and growth of leaping mullet from the Messolonghi -Etoliko lagoon system (western Greek coast) were studied. Age and growth determinations were based upon otolith samples taken from 537 fish. Marginal increment analysis was used to validate age determination. Annulus formation took place around November each year. The back-calculated lengths at age estimated from the otoliths showed no differences between sub-areas of the lagoon system and the recorded limited between-years variability showed no persistent temporal pattern. The maximum age of leaping mullet in the Messolonghi - Etoliko lagoon was 5 years for males and 6 years for females. The von Bertalanffy equation (L‡=32.99±1.25 cm, k=0.258 ±0.017 year-1, t0=-0.47±0.04 year) accurately describes the growth of the total length of leaping grey mullet for all life stages (fry, juveniles and adults). A large spread and length overlap characterized the age groups. The estimated Length-Weight relationships were common for the two sexes (W=0.0079L3.01)

Visibility and acceptance of discrete-sampling artifacts in visual displays

Ph. D. ThesisDigital visual displays are aimed to provide an illusion of a continuous reality through a discrete presentation of visual information. This thesis explored three topics on (i) angular, (ii) spatial, and (iii) temporal sampling characteristics, related to distortion visibility, acceptance, and discomfort. In the first topic, we addressed the issue of optimizing the view density in continuous parallax visualization by replicating the changing views of a 3-D object for a moving observer. We measured the visibility of the related artifacts and evaluated the performance of full-reference visual quality metrics. We found that the state-of-the-art metrics can indirectly characterize artifact visibility and established a quantitative relationship for threshold estimation on varying conditions. The second topic addressed the relation of the contrast sensitivity function (CSF) to adaptation luminance and specifically its asymptotic behavior at high light levels essential to modern high-luminance displays. Using a custombuilt system, we measured the CSF at relatively high luminance levels and spatial frequency range, integrating our dataset to the existing research. We found a gradual transition among the linear to DeVries-Rose to Weber regions with steeper slopes for higher frequencies and lower luminance. A further decreasing region was located at low to intermediate frequencies. Following this construct, we adopted a model consisting of central elements in the visual signal processing and proposed an eight-parameter form for the CSF in the luminance domain. The final topic addressed the effects of frame rate on distortion acceptance and its impact on visual discomfort during regular display use. We assessed the perceived symptoms, preference, and task performance under varying conditions. The measurements indicated that for nondemanding everyday tasks, the frame rate could be reasonably reduced without severe effects on the observer; however, this tolerance diminished under more dynamic content. A potential association of discomfort with the blinking activity was also discussedThe European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 676401, European Training Network on Full Parallax Imaging and Huawei Technologies Co., Lt

Historical overview of spinal deformities in ancient Greece

Little is known about the history of spinal deformities in ancient Greece. The present study summarizes what we know today for diagnosis and management of spinal deformities in ancient Greece, mainly from the medical treatises of Hippocrates and Galen. Hippocrates, through accurate observation and logical reasoning was led to accurate conclusions firstly for the structure of the spine and secondly for its diseases. He introduced the terms kyphosis and scoliosis and wrote in depth about diagnosis and treatment of kyphosis and less about scoliosis. The innovation of the board, the application of axial traction and even the principle of trans-abdominal correction for correction of spinal deformities have their origin in Hippocrates. Galen, who lived nearly five centuries later impressively described scoliosis, lordosis and kyphosis, provided aetiologic implications and used the same principles with Hippocrates for their management, while his studies influenced medical practice on spinal deformities for more than 1500 years

Advantages of the Ilizarov external fixation in the management of intra-articular fractures of the distal tibia

<p>Abstract</p> <p>Background</p> <p>Treatment of distal tibial intra-articular fractures is challenging due to the difficulties in achieving anatomical reduction of the articular surface and the instability which may occur due to ligamentous and soft tissue injury. The purpose of this study is to present an algorithm in the application of external fixation in the management of intra-articular fractures of the distal tibia either from axial compression or from torsional forces.</p> <p>Materials and methods</p> <p>Thirty two patients with intra-articular fractures of the distal tibia have been studied. Based on the mechanism of injury they were divided into two groups. Group I includes 17 fractures due to axial compression and group II 15 fractures due to torsional force. An Ilizarov external fixation was used in 15 patients (11 of group I and 4 of group II). In 17 cases (6 of group I and 11 of group II) a unilateral hinged external fixator was used. In 7 out of 17 fractures of group I an additional fixation of the fibula was performed.</p> <p>Results</p> <p>All fractures were healed. The mean time of removal of the external fixator was 11 weeks for group I and 10 weeks for group II. In group I, 5 patients had radiological osteoarthritic lesions (grade III and IV) but only 2 were symptomatic. Delayed union occurred in 3 patients of group I with fixed fibula. Other complications included one patient of group II with subluxation of the ankle joint after removal of the hinged external fixator, in 2 patients reduction found to be insufficient during the postoperative follow up and were revised and 6 patients had a residual pain. The range of ankle joint motion was larger in group II.</p> <p>Conclusion</p> <p>Intra-articular fractures of the distal tibia due to axial compression are usually complicated with cartilaginous problems and are requiring anatomical reduction of the articular surface. Fractures due to torsional forces are complicated with ankle instability and reduction should be augmented with ligament repair, in order to restore normal movement of talus against the mortise. Both Ilizarov and hinged external fixators are unable to restore ligamentous stability. External fixation is recommended only for fractures of the ankle joint caused by axial compression because it is biomechanically superior and has a lower complication rate.</p