74 research outputs found
Morphological characterization of the blood cells in the endangered Sicilian endemic pond turtle,Emys trinacris(Testudines: Emydidae)
In this study, measurements of morphological parameters, sizes and frequencies of peripheral blood cells (erythrocytes,
leukocytes, thrombocytes) on blood smear preparation devices stained with May-Grünwald stain were evaluated for both
sexes in 20 Emys trinacris (Testudines: Emydidae) specimens. Erythrocytes were higher in male than in female specimens.
The leukocyte of E. trinacris contains eosinophil, basophil, monocyte, heterophil and lymphocyte. The eosinophil was higher
in males than in females whereas lymphocytes were higher in females than in males. The erythrocyte morphological
parameters (EL [erythrocyte length], EW [erythrocyte width], L/W [length/width], ES [erythrocyte size]) were compared
with the same data from Emys orbicularis s.l, and from species belonging to other chelonian genera. The erythrocyte size did
not vary within the studied Palearctic Emys taxa, whereas it proved to differ from that observed in other chelonians
Markovian evolution of quantum coherence under symmetric dynamics
Both conservation laws and practical restrictions impose symmetry constraints on the dynamics of open quantum systems. In the case of time-translation symmetry, which arises naturally in many physically relevant scenarios, the quantum coherence between energy eigenstates becomes a valuable resource for quantum information processing. In this work we identify the minimum amount of decoherence compatible with this symmetry for a given population dynamics. This yields a generalisation to higher-dimensional systems of the relation T2 2T1 for qubit decoherence and relaxation times. It also enables us to witness and assess the role of non-Markovianity as a resource for coherence preservation and transfer. Moreover, we discuss the relationship between ergodicity and the ability of Markovian dynamics to indenitely sustain a superposition of diferent energy states. Finally, we establish a formal connection between the resource-theoretic and the master equation approaches to thermodynamics, with the former being a non-Markovian generalisation of the latter. Our work thus brings the abstract study of quantum coherence as a resource towards the realm of actual physical applications
The role of LINEs and CpG islands in dosage compensation on the chicken Z chromosome
Most avian Z genes are expressed more highly in ZZ males than ZW females, suggesting that chromosome-wide mechanisms of dosage compensation have not evolved. Nevertheless, a small percentage of Z genes are expressed at similar levels in males and females, an indication that a yet unidentified mechanism compensates for the sex difference in copy number. Primary DNA sequences are thought to have a role in determining chromosome gene inactivation status on the mammalian X chromosome. However, it is currently unknown whether primary DNA sequences also mediate chicken Z gene compensation status. Using a combination of chicken DNA sequences and Z gene compensation profiles of 310 genes, we explored the relationship between Z gene compensation status and primary DNA sequence features. Statistical analysis of different Z chromosomal features revealed that long interspersed nuclear elements (LINEs) and CpG islands are enriched on the Z chromosome compared with 329 other DNA features. Linear support vector machine (SVM) classifiers, using primary DNA sequences, correctly predict the Z compensation status for >60% of all Z-linked genes. CpG islands appear to be the most accurate classifier and alone can correctly predict compensation of 63% of Z genes. We also show that LINE CR1 elements are enriched 2.7-fold on the chicken Z chromosome compared with autosomes and that chicken chromosomal length is highly correlated with percentage LINE content. However, the position of LINE elements is not significantly associated with dosage compensation status of Z genes. We also find a trend for a higher proportion of CpG islands in the region of the Z chromosome with the fewest dosage-compensated genes compared with the region containing the greatest concentration of compensated genes. Comparison between chicken and platypus genomes shows that LINE elements are not enriched on sex chromosomes in platypus, indicating that LINE accumulation is not a feature of all sex chromosomes. Our results suggest that CpG islands are not randomly distributed on the Z chromosome and may influence Z gene dosage compensation status
Cell size is positively correlated between different tissues in passerine birds and amphibians, but not necessarily in mammals
We examined cell size correlations between tissues, and cell size to body mass relationships in passerine birds, amphibians and mammals. The size correlated highly between all cell types in birds and amphibians; mammalian tissues clustered by size correlation in three tissue groups. Erythrocyte size correlated well with the volume of other cell types in birds and amphibians, but poorly in mammals. In birds, body mass correlated positively with the size of all cell types including erythrocytes, and in mammals only with the sizes of some cell types. Size of mammalian erythrocytes correlated with body mass only within the most taxonomically uniform group of species (rodents and lagomorphs). Cell volume increased with body mass of birds and mammals to less than 0.3 power, indicating that body size evolved mostly by changes in cell number. Our evidence suggests that epigenetic mechanisms determining cell size relationships in tissues are conservative in birds and amphibians, but less stringent in mammals. The patterns of cell size to body mass relationships we obtained challenge some key assumptions of fractal and cellular models used by allometric theory to explain mass-scaling of metabolism. We suggest that the assumptions in both models are not universal, and that such models need reformulation
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