Search results for "MORPHOLOGY"
showing 10 items of 1425 documents
Weak phylogenetic effects on ecological niches of Sylvia warblers
2003
To understand the evolution of ecological niches it is important to know whether niche evolution is constrained by phylogeny. We approached this question for Sylvia warblers by testing if closely related species are more similar in 20 ecologically relevant morphological traits than distantly related species. Phylogenetic relatedness was quantified using a molecular phylogeny based on the mitochondrial cytochrome b gene. By Principal Component Analysis (PCA) two major niche axes were extracted. We tested the individual ecomorphological traits and the positions of the species on the PCA axes for phylogenetic effects using Mantel tests. The results demonstrated small but significant phylogenet…
Chilocoris capensis n. sp., the first species of the genus Chilocoris Mayr, 1865 (Hemiptera: Heteroptera: Cydnidae) recorded in the Republic of South…
2016
Chilocoris capensis n. sp. collected from fallen ripe figs of broom cluster fig Ficus sur Forsskal, 1775, the first burrower bug species of the genus Chilocoris Mayr, 1865 recorded in the Republic of South Africa, is described and compared with Chilocoris laevicollis Horvath, 1919, the morphologically most closely allied Afrotropical species. Additionally, an annotated checklist of burrower bug species recorded in the Republic of South Africa is provided. The known biology of Afrotropical Chilocoris species is briefly summarized.
New Afrotropical species of the genus Coridiellus J.A. Lis, 1990 with a key to its species (Hemiptera: Heteroptera: Dinidoridae)
2020
Coridiellus pseudocyclopeltus, a new species of the dinidorid subfamily Dinidorinae, is described from Zaire and is compared with Coridiellus cyclopeltus (Distant, 1890). It is the seventh species of this genus known from Afrotropical Region. A key to all the species of the genus Coridiellus is also provided. Male parameres are used for identification and their photographs are given for the first time for all species of the genus.
Computer assisted sperm morphometry in mammals: a review.
2014
Computer-assisted sperm morphometry analysis (CASMA or ASMA) systems were developed to reduce the subjectivity of sperm morphology assessement. This review focuses on a complete description of the CASMA technique, including recent developments, factors of variation, results in the different species and possible applications. Techniques to study sperm morphometry include light microscopy, phase-contrast microscopy and, more recently, fluorescence microscopy. Most published studies on sperm morphometry have been centered on the whole sperm heads, although some of them also measured other parts of the sperm structure, such as the nucleus, acrosome, midpiece or flagellum. The independent study …
Bizarre alterations of the morphology of pineal synaptic bodies under constant light and an evaluation of suitable 3D-reconstruction software
2004
Three dimensional (3D) reconstruction and modelling software was evaluated to find a procedure suitable for visualization of small subcellular structures in transmission electron microscope images. The method applied in this study demonstrates bizarre alterations of the structure of synaptic bodies (SBs) in pinealocytes of the guinea-pig pineal gland caused by constant illumination. It can, in general, be used for any 3D reconstruction from serial sections. Pineal glands of five guinea-pigs (two kept under a LD cycle of 12:12 h; three kept in constant light, for 4 months) were investigated. SBs consist of an electron-dense centre with attached vesicles. Under normal lighting conditions most…
Facial patterns in Cercopithecoidea and Hominoidea: a geometric approach.
2006
The maxillofacial and orbital compartments of the primate skull contribute to the ontogenetic and phylogenetic variability of the viscerocranium and are of crucial evolutionary relevance. As the form of organisms changes depending on endo- and exogenous factors, metrical evaluation of specific adaptations and incorporation of the results into a biological framework could be helpful in identifying valid characters for separation of taxa (e.g. family, genus, and species) and in understanding divergence and convergence. During the last two decades a morphometric "revolution" heralded by Rohlf & Marcus (1993), Adams et al. (2004) and Oxnard (2004) brought about a synthesis of traditional quanti…
Analysis of synaptic bodies in the Sprague–Dawley rat pineal gland under extreme photoperiods
2007
Synaptic bodies (SBs) are small, prominent organelles in pinealocytes, most probably involved in signal transduction processes. To check the influence of the photoperiod on their shape plasticity and number we chose two extreme lighting conditions, i.e. 20 h of illumination followed by 4 h of darkness (LD 20:4) versus (LD 4:20). Pineal glands were assessed at 0, 4 and 13 h after dark onset. Under both conditions reconstructed SBs were plates or ribbons but never spheres and there were no obvious differences in morphology. Photoperiodic changes in SB profile size and number were investigated: application of the established method for SB quantification based on single section profile counts (…
Strain differences in the ratio of synaptic body types in photoreceptors of the rat retina.
1993
In the retinal outer plexiform layer of seven different rat strains, synaptic bodies (SB) were counted and, according to their morphology, characterized as synaptic ribbons (SR), synaptic spheres (SS) or intermediate structures. It was found that absolute SB numbers showed relatively small variations while SR/SS ratios differed considerably between the strains investigated. These results are discussed with respect to retinal pigmentation and to formation and degradation, respectively, of synaptic ribbons.
Characterisation of peripheral bone mineral density in youth at risk of secondary osteoporosis - a preliminary insight.
2020
Objectives: To describe peripheral long bone material and structural differences in youth at risk of secondary osteoporosis across disease-specific profiles. Methods: Upper- and lower limbs of children and adolescents were scanned at 4% distal and 66% mid-shaft sites using peripheral Quantitative Computed Tomography sub-categorised as (1) increased risk of secondary osteoporosis (neuromuscular disorders; chronic diseases; endocrine diseases; inborn errors of metabolism; iatrogenic conditions), (2) low motor competence and (3) non-affected controls. Results: Children with disease-specific profiles showed a range of bone deficits compared to the control group with these predominantly indicate…
A minimally invasive methodology based on morphometric parameters for day 2 embryo quality assessment.
2014
[EN] The risk of multiple pregnancy to maternal fetal health can be minimized by reducing the number of embryos transferred. New tools for selecting embryos with the highest implantation potential should be developed. The aim of this study was to evaluate the ability of morphological and morphometric variables to predict implantation by analysing images of embryos. This was a retrospective study of 135 embryo photographs from 112 IVF ICSI cycles carried out between January and March 2011. The embryos were photographed immediately before transfer using Cronus 3 software. Their images were analysed using the public program ImageJ. Significant effects (P < 0.05), and higher discriminant power …