Bohr space in six dimensions

A conformal factor in the Bohr model embeds Bohr space in six dimensions, revealing the $O(6)$ symmetry and its contraction to the $E(5)$ at infinity. Phenomenological consequences are discussed after the re-formulation of the Bohr Hamiltonian in six dimensions on a five sphere

A+2n compound nuclei and the unitary limit in nuclear physics

This contribution discusses a new perception of the structure of compound nuclei by introducing intermediate states of the Feshbach formalism of nuclear reactions in the Interacting Boson Model of nuclear structure. The stake is to explore the manifestation of the unitary limit in heavy, even-even nuclei. Interactions that govern Feshbach resonances of cold and dilute atomic gases suggest the formulation of an IBM-compound Hamiltonian for scattering two neutrons (2n) from a heavy, even-even target (A). The solutions of the corresponding coupled channel equations host a 2n-IBM state resonance. It turns out that the unitary limit is measurable in a heavy A+2n compound nucleus at low temperatures. That measurement is feasible through the fluctuations of the cross-sections that tune the 2n-A scattering length.Comment: Contribution to 13th International Spring Seminar on Nuclear Physics Perspectives and Challenges in Nuclear Structure after 70 Years of Shell Model (ISS 2022) 14/05/2022 - 20/05/2022 Sant'Angelo, Ital

Bohr Hamiltonian with deformation-dependent mass term for the Kratzer potential

The Deformation Dependent Mass (DDM) Kratzer model is constructed by considering the Kratzer potential in a Bohr Hamiltonian, in which the mass is allowed to depend on the nuclear deformation, and solving it by using techniques of supersymmetric quantum mechanics (SUSYQM), involving a deformed shape invariance condition. Analytical expressions for spectra and wave functions are derived for separable potentials in the cases of gamma-unstable nuclei, axially symmetric prolate deformed nuclei, and triaxial nuclei, implementing the usual approximations in each case. Spectra and B(E2) transition rates are compared to experimental data. The dependence of the mass on the deformation, dictated by SUSYQM for the potential used, moderates the increase of the moment of inertia with deformation, removing a main drawback of the model.Comment: 27 pages, 6 figures, 8 tables. arXiv admin note: text overlap with arXiv:1103.593

Συλλογικά πυρηνικά πρότυπα με μάζα εξαρτημένη από τη παραμόρφωση επιλύσιμα με μεθόδους υπερσυμμερικής κβαντομηχανικής

138 σ.Σε αυτή τη διδακτορική διατριβή η Χαμιλτονιανή του Bohr τροποποιείται αφήνοντας τη παράμετρο μάζας να εξαρτάται από τη θέση (τετραπολική παραμόρφωση), ακολουθώντας τη μέθοδο των Quesne και Tkachuk. Η ακριβής επιλυσιμότητα της προκύπτουσας Χαμιλτονιανής επιτυγχάνεται με μεθόδους υπερσυμμετρικής κβανοτμηχανικής. Αποδεικνύεται ότι για μια ειδική επιλογή των παραμέτρων που εισάγουν οι Quesne και Tkachuk η εξάρτηση της μάζας από τη θέση ισοδυναμεί με ένα παράγοντα συμμορφοποίησης (conformal factor). Με αυτό το τρόπο προτείνεται ένα γεωμετρικό πλαίσιο για την ανάλυση της σχέσης της Χαμιλτονιανής Bohr με το πρότυπο των αλληλεπιδρώντων μποζονίων (Interacting Boson Model) της πυρηνικης δομής.In this doctoral dissertation the Bohr Hamiltonian is modified by letting the mass parameter to depend on the position (quadrupole deformation), following the method of Quesne and Tkachuk. The exact solvability of the deformation-dependent mass Bohr Hamiltonian is achieved by supersymmetric quantum mechanics. It is proved that for a special choice of the parameters of Quesne and Tkachuk the dependence of the mass on the position is equivalent to a conformal factor. In this way a geometrical framework is proposed for the analysis of the relation of the Bohr Hamiltonian to the Interacting Boson Model of nuclear structure.Παναγιώτης Ε. Γεωργουδή

Εκφυλισμοί και συμμετρίες στην κρίσιμη περιοχή του Interacting Boson Model

88 σ.Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) "Φυσική και Τεχνολογικές Εφαρμογές"Εκφυλισμοί και συμμετρίες στη κρίσιμη περιοχή του Interacting Boson ModelΠαναγιώτης Ε. Γεωργουδή

A genetic linkage map of the hermaphrodite teleost fish Sparus aurata L.

The gilthead sea bream (Sparus aurata L.) is a marine fish of great importance for fisheries and aquaculture. It has also a peculiar sex-determination system, being a protandrous hermaphrodite. Here we report the construction of a first-generation genetic linkage map for S. aurata, based on 204 microsatellite markers. Twenty-six linkage groups (LG) were found. The total map length was 1241.9 cM. The ratio between sex-specific map lengths was 1:1.2 (male:female). Comparison with a preliminary radiation hybrid (RH) map reveals a good concordance, as all markers located in a single LG are located in a single RH group, except for Ad-25 and CId-31. Comparison with the Tetraodon nigroviridis genome revealed a considerable number of evolutionary conserved regions (ECRs) between the two species. The mean size of ECRs was 182 bp (sequence identity 60–90%). Forty-one ECRs have a known chromosomal location in the pufferfish genome. Despite the limited number of anchoring points, significant syntenic relationships were found. The linkage map presented here provides a robust comparative framework for QTL analysis in S. aurata and is a step toward the identification of genetic loci involved both in the determination of economically important traits and in the individual timing of sex reversal

Landscape genomics and biased FST approaches reveal single nucleotide polymorphisms under selection in goat breeds of North-East Mediterranean

<p>Abstract</p> <p>Background</p> <p>In this study we compare outlier loci detected using a <it>F<smcaps>ST </smcaps></it>based method with those identified by a recently described method based on spatial analysis (SAM). We tested a panel of single nucleotide polymorphisms (SNPs) previously genotyped in individuals of goat breeds of southern areas of the Mediterranean basin (Italy, Greece and Albania). We evaluate how the SAM method performs with SNPs, which are increasingly employed due to their high number, low cost and easy of scoring.</p> <p>Results</p> <p>The combined use of the two outlier detection approaches, never tested before using SNP polymorphisms, resulted in the identification of the same three loci involved in milk and meat quality data by using the two methods, while the <it>F<smcaps>ST </smcaps></it>based method identified 3 more loci as under selection sweep in the breeds examined.</p> <p>Conclusion</p> <p>Data appear congruent by using the two methods for <it>F<smcaps>ST </smcaps></it>values exceeding the 99% confidence limits. The methods of <it>F<smcaps>ST </smcaps></it>and SAM can independently detect signatures of selection and therefore can reduce the probability of finding false positives if employed together. The outlier loci identified in this study could indicate adaptive variation in the analysed species, characterized by a large range of climatic conditions in the rearing areas and by a history of intense trade, that implies plasticity in adapting to new environments.</p

The Mediterranean Decision Support System for Marine Safety dedicated to oil slicks predictions

In the Mediterranean sea the risk from oil spill pollution is high due to the heavy traffic of merchant vessels for transporting oil and gas, especially after the recent enlargement of the Suez canal and to the increasing coastal and offshore installations related to the oil industry in general. The basic response to major oil spills includes different measures and equipment. However, in order to strengthen the maritime safety related to oil spill pollution in the Mediterranean and to assist the response agencies, a multi-model oil spill prediction service has been set up, known as MEDESS-4MS (Mediterranean Decision Support System for Marine Safety). The concept behind the MEDESS-4MS service is the integration of the existing national ocean forecasting systems in the region with the Copernicus Marine Environmental Monitoring Service (CMEMS) and their interconnection, through a dedicated network data repository, facilitating access to all these data and to the data from the oil spill monitoring platforms, including the satellite data ones, with the well established oil spill models in the region. The MEDESS-4MS offer a range of service scenarios, multi-model data access and interactive capabilities to suite the needs of REMPEC (Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea) and EMSA-CSN (European Maritime Safety Agency-CleanseaNet)

The experience of low back pain in people with incomplete spinal cord injury in the USA, UK and Greece

Engineering and Physical Sciences Research Council's (EPSRC