University of Crete

About: University of Crete is a education organization based out in Rethymno, Greece. It is known for research contribution in the topics: Population & Galaxy. The organization has 8681 authors who have published 21684 publications receiving 709078 citations. The organization is also known as: Panepistimio Kritis.

Skeletal anomalies in reared European fish larvae and juveniles. Part 2: main typologies, occurrences and causative factors

Abstract: The presence of skeletal anomalies in farmed teleost fish is currently a major problem in aquaculture, entailing economical, biological and ethical issues. The common occurrence of skeletal abnormalities in farmed fish and the absence of effective solutions for avoiding their onset or definitely culling out the affected individuals as early as possible from the productive cycle, highlight the need to improve our knowledge on the basic processes regulating fish skeletogenesis and skeletal tissues differentiation, modelling and remodelling. Severe skeletal anomalies may actually occur throughout the entire life cycle of fish, but their development often begins with slight aberrations of the internal elements. Comprehensive investigation efforts conducted on reared larvae and juveniles could provide a great contribution in filling the gap in knowledge, as skeletogenesis and skeletal tissue differentiation occur during these early life stages. The aim of this review is to provide a synthetic but comprehensive picture of the actual knowledge on the ontogeny, typologies and occurrence of skeletal anomalies, and on the proposed causative factors for their onset in larvae and juveniles of European farmed fish. The state-of-art of knowledge of these issues is analysed critically intending to individualize the main gaps of knowledge that require to be filled, in order to optimize the morphological quality of farmed juveniles.

Pathogenesis, diagnosis and management of neuropsychiatric SLE manifestations

Abstract: Neuropsychiatric events are common in patients with systemic lupus erythematosus (SLE), but less than one-third of these events can be directly attributed to SLE. Increased generalized SLE disease activity or damage, previous or concurrent major neuropsychiatric SLE (NPSLE) events, and persistently positive moderate-to-high antiphospholipid antibody titers are established risk factors, and their presence could facilitate proper attribution to the disease itself. Diagnostic evaluation is guided by the presenting manifestation; MRI is used to visualize brain or spinal pathologies. For neuropsychiatric events believed to reflect an immune or inflammatory process, or when these events occur in the context of active generalized disease, evidence (primarily from uncontrolled studies) supports the use of glucocorticoids alone or in combination with immunosuppressive therapy. Antiplatelet and/or anticoagulation therapy is recommended for NPSLE manifestations related to antiphospholipid antibodies, especially for thrombotic cerebrovascular disease. For the future, we anticipate that novel biomarkers and advanced neuroimaging tests will better define the underlying pathologic mechanisms of SLE-related neuropsychiatric disease, and help guide therapeutic decisions.

Carbon and nitrogen abundance variations on the main sequence of 47 Tucanae

Abstract: The FOCAP multi-object fibre optic system on the AAT has been used to obtain spectra for a sample of more than a hundred faint stars in the globular cluster 47 Tuc (NGC 104), from the base of the giant branch to about a magnitude below the main-sequence turn-off. The spectra cover the ultraviolet and blue bands of CN and the G band of CH. Quantitative abundances have been derived by comparing the observations with synthetic spectra. The main-sequence stars can be divided into two approximately equal groups, one having N enhanced by a factor of ∼ 7, and C depleted by 40 per cent, relative to the other, similar to what is inferred for the red giants. The mean heavy-element abundance, as measured by Ca or Fe, differs between the two groups by no more than 0.01 ± 0.05 dex. All the available abundance data indicate that the atmospheres of 47 Tuc stars contain different amounts of material which has been processed through the CNO cycle, but not through more advanced stages of nucleosynthesis. In the red giants, this could be a result of the convective dredge-up of processed material from deep within the stars themselves, as occurs in some more metal-poor clusters. However, stars on the upper main sequence of globular clusters do not have convective envelopes, while any deep mixing there would have consequences incompatible with other observational data. Thus it seems that the main-sequence C and N variations must be either primordial or caused by a pollution mechanism. The similarity of the bimodal abundance patterns among the dwarfs and giants then suggests that the dredge up of CNO-cycled material is not the dominant process in the red giants either, at least not in 47 Tuc. The CNO-processed material seems most likely to have come from intermediate-mass stars on the asymptotic giant branch; various mechanisms by which such material might appear in the main-sequence stars are discussed. Explanations involving a truly primordial origin, or having successive generations of stars, seem to require rather special ‘tuning’. A somewhat speculative alternative self-enrichment process is proposed, in which stellar winds from intermediate-mass stars were captured by existing low-mass stars, early in the life of the cluster. Whatever the mechanism, the abundance data presumably contain important clues about the formation and early evolution of globular clusters.