Retinal Specializations In The Eyes Of Deep-Sea Teleosts

Although living beyond the penetration limits of sunlight, many deep-sea teleosts possess large eyes, lenses capable of accommodation, and various adaptations for increasing sensitivity and extending their visual field. However, little is known of the extent of the visual field and whether the spatial resolving power of the eye is constant across the retina. In order to examine whether these fish are specialized for acute vision in particular regions of the visual field, retinal wholemounts were used to examine the regional differences in the density of retinal ganglion cells in 16 species from different depths, habitats and photic zones. It was found that the retinal ganglion cell topography changes markedly across the retina with a density range of 6.3-50.6 x 10/3 cells mm -2 in a pattern unique to each species. A number of mesopelagic species including the lanternfishes, Lampanyctus macdonaldi and Myctophum punctatum possess a concentric increase in cell density towards the retinal margins, putatively enhancing peripheral vision. Three tubular-eyed species including Scopelarchus michaelsarsi possess an area centralis in the centro-lateral region of the main retina supporting the premise that this specialization receives a focused image. Some benthic species such as the smoothhead Rouleina attrita and the searsid Searsia koefoedi also boast a structural specialization or fovea in temporal retina with centro-peripheral cell gradients exceeding 30:1. Benthic species such as the tripodfish Bathypterois dubius possess two regional increases in ganglion cell density or areae centrales, one nasal and the other temporal, thereby increasing spatial resolving power in the caudal and rostral visual fields, respectively. These quantitative analyses suggest that deep-sea fishes, like their shallow-water counterparts, also use a specific region of their visual field for acute vision. This may be an advantage for the detection and localization of bioluminescent light sources

Caracterización citológica de hepatopatías en perros y gatos

Diferentes técnicas diagnósticas complementarias se han aplicado durante losúltimos años en medicina veterinaria. Debido a su implementación se han realizado diagnósticosnovedosos en animales, pero aún es necesario determinar sensibilidad y especificidadde las mismas. Para la evaluación de las enfermedades hepáticas se dispone fundamentalmentede técnicas no invasivas, como las pruebas bioquímicas, la ultrasonografía y otras.La realización de biopsias es fundamental en muchos casos para determinar la causa o elpronóstico de las alteraciones encontradas, por lo cual todas estas técnicas deben considerarsecomo parte de un sistema de diagnóstico integrado. Se describen aquí los resultadosde la realización de la técnica de punción con aguja fina guiada por ecografía, aplicada aveintidós pacientes con sintomatología hepática, que concurrieron al Hospital de Clínicas dela Facultad de Ciencias Veterinarias de la UNNE durante el primer semestre del año 2007.Se detallan hallazgos citológicos significativos para la caracterización de diferentes hepatopatíasen perros y gatos

Mitochondrial differentiation, introgression and phylogeny of species in the Tegenaria atrica group (Araneae, Agelenidae)

The relationships between the three members of the Tegenaria atrica group (T. atrica, T. saeva and T. gigantea) were examined with DNA sequence data from mitochondrial CO1, 16S rRNA, tRNAleu(CUN) and ND1 genes. Members of this group of large house spiders have overlapping distributions in western Europe and hybridize with each other to a variable degree. The close relatedness of all three species was supported by all analyses. T. saeva and T. gigantea are more closely affiliated than either is to T. atrica. Haplotypes clearly assignable to T. gigantea were also present in many specimens of T. saeva suggesting asymmetrical introgression of mtDNA from T. gigantea into T. saeva. Molecular clock calibrations (CO1) suggest that deeper divisions within the genus Tegenaria may be in excess of 10 million years old, and that the evolutionary history of the T. atrica group has been moulded by Quaternary glacial-interglacial cycles

Realistic Elbow Flesh Deformation Based on Anthropometrical Data for Ergonomics Modeling

The human model for ergonomic simulation has improved in terms of its reliability and appearance and yet there seems to be less attention paid to create a realistic and accurate flesh deformation around the joint. This study, a part of ongoing research, proposes a combination of manual and automatic (3D body scanner) measurements to create a database for flesh deformation prediction i.e. flesh deformation area and cross section changes, around the elbow joint. The database consists of two race groups i.e., Caucasian and Asian (23 subjects, 11 males and 12 females), which were carefully chosen to represent a variety of height and body type. The prediction results for both flesh deformation area and cross section changes are discussed as well as their relevance for the next stage of the study