Effective nucleon mass and the nuclear caloric curve

Assuming a schematic form of the nucleon effective mass as a function of nuclear excitation energy and mass, we provide a simple explanation for understanding the experimentally observed mass dependence of the nuclear caloric curve. It is observed that the excitation energy at which the caloric curve enters into a plateau region, could be sensitive to the nuclear mass evolution of the effective nucleon mass.Comment: 5 pages, 5 figures, Accepted for publication in Phys. Rev. C. Minor changes mad

GEO-ELECTRICAL MAPPING OF BEACHROCK IN VATERA BEACH, LESVOS

Tο Beachrock (Br ή παραλιακοί ψαμμίτες) εμφανίζεται σε παράκτιες ζώνες και έχει σύνθετο ρόλο όσον αφορά στη μορφοδυναμική εξέλιξη τους. Αν και το Br έχει μελετηθεί ευρέως, ωστόσο, δύο βασικά θέματα χρήζουν επιπρόσθετης έρευνας. Το πρώτο αφορά στη σημασία της αλληλεπίδρασης του δυναμικά μεταβαλλόμενου παράκτιου περιβάλλοντος με την χρονικά μεταβαλλόμενη επιφανειακή και υπόγεια υδρογεωλογική ισορροπία. Το δεύτερο θέμα έχει να κάνει με τη χωρική κατανομή και την εξέλιξη του Br σε σχέση με συγκεκριμένο περιβάλλον που το “φιλοξενεί”. H παρούσα εργασία αναδεικνύει τη μέθοδο της ειδικής ηλεκτρικής αντίστασης του υπεδάφους, ως ένα σύγχρονο εργαλείο που μπορεί να συμβάλει στη μελέτη των παραπάνω προβληματισμών. Η έρευνα περιέλαβε μετρήσεις με τη γεωηλεκτρική μέθοδο συνεχούς ρεύματος κατά μήκος δύο τομών στην παραλία των Βατερών της Λέσβου, όπου παρατηρούνται σημαντικές επιφανειακές εμφανίσεις Br. Πραγματοποιήθηκαν δώδεκα γεωηλεκτρικές βυθοσκοπήσεις, με ανάπτυγμα ηλεκτροδίων Axial Pole-Dipole. Οι μετρήσεις της ειδικής ηλεκτρικής αντίστασης επέτρεψαν μία έμμεση εκτίμηση του TDS, το οποίο απεικονίζει την διεπιφάνεια γλυκού-θαλασσινού νερού. Κατά την ερμηνεία του γεωηλεκτρικού μοντέλου αναδείχθηκαν δύο σχηματισμοί που αντιστοιχούν σε Br. Ο πρώτος αποτελεί επέκταση του Br προς την ξηρά και ο δεύτερος πιστεύεται ότι είναι Br σε πρώιμο στάδιο ωρίμανσης.Beachrock (Br) is encountered on the coastal zones, playing an important but also complex role in their morphodynamic evolution. Although Br has been widely studied, two important issues require further investigation. The first concerns the importance of the interaction of the dynamically changing coastal environment with the temporal changing surficial and underground hydrogeological balance. The second has to do with the spatial distribution and the evolution of Br with respect to the specific “host” coastal zone geo environment. This paper designates the electrical resistivity method as a tool that contribute in arguing in the abovementioned issues. The research comprised subsurface measurements with the DC resistivity method along two profiles located on Vatera beach (Lesvos Island), where there is a significant Br outcrops. Twelve geoelectric soundings were carried out using the Axial Pole-Dipole electrode array. The electrical resistively measurements permitted an indirect estimation of TDS, which depicts the coastal interface of fresh water - sea water. The interpreted geoelectric model shows two thin formations attributed to Br. The first is the inland extension of the Br outcrop and the second it is believed to be a primary stage of Br build up

Nuclear expansion and symmetry energy of hot nuclei

The decrease in the symmetry energy of hot nuclei populated in $^{58}$Ni + $^{58}$Ni, $^{58}$Fe + $^{58}$Ni and $^{58}$Fe + $^{58}$Fe reactions at beam energies of 30, 40, and 47 MeV/nucleon, as a function of excitation energy is studied. It is observed that this decrease is mainly a consequence of increasing expansion or decreasing density rather than the increasing temperature. The results are in good agreement with the recently reported microscopic calculation based on the Thomas-Fermi approach. An empirical relation to study the symmetry energy of finite nuclei in various mass region is proposed.Comment: 10 pages, 2 figure

Analysis of fragment yield ratios in the nuclear phase transition

The critical phenomena of the liquid-gas phase transition has been investigated in the reactions 78,86Kr+58,64Ni at beam energy of 35 MeV/nucleon using the Landau free energy approach with isospin asymmetry as an order parameter. Fits to the free energy of fragments showed three minima suggesting the system to be in the regime of a first order phase transition. The relation m =-{\partial}F/{\partial}H, which defines the order parameter and its conjugate field H, has been experimentally verified from the linear dependence of the mirror nuclei yield ratio data, on the isospin asymmetry of the source. The slope parameter, which is a measure of the distance from a critical temperature, showed a systematic decrease with increasing excitation energy of the source. Within the framework of the Landau free energy approach, isoscaling provided similar results as obtained from the analysis of mirror nuclei yield ratio data. We show that the external field is primarily related to the minimum of the free energy, which implies a modification of the source concentration \Delta used in isospin studies

Analysis of fragment yield ratios in the nuclear phase transition

The critical phenomena of the liquid-gas phase transition has been investigated in the reactions 78,86Kr+58,64Ni at beam energy of 35 MeV/nucleon using the Landau free energy approach with isospin asymmetry as an order parameter. Fits to the free energy of fragments showed three minima suggesting the system to be in the regime of a first order phase transition. The relation m =-{\partial}F/{\partial}H, which defines the order parameter and its conjugate field H, has been experimentally verified from the linear dependence of the mirror nuclei yield ratio data, on the isospin asymmetry of the source. The slope parameter, which is a measure of the distance from a critical temperature, showed a systematic decrease with increasing excitation energy of the source. Within the framework of the Landau free energy approach, isoscaling provided similar results as obtained from the analysis of mirror nuclei yield ratio data. We show that the external field is primarily related to the minimum of the free energy, which implies a modification of the source concentration \Delta used in isospin studies

ACR Appropriateness Criteria® Spinal Bone Metastases

The spine is a common site of involvement in patients with bone metastases. Apart from pain, hypercalcemia, and pathologic fracture, progressive tumor can result in neurologic deterioration caused by spinal cord compression or cauda equina involvement. The treatment of spinal bone metastases depends on histology, site of disease, extent of epidural disease, extent of metastases elsewhere, and neurologic status. Treatment recommendations must weigh the risk-benefit profile of external beam radiation therapy (EBRT) for the particular individual's circumstance, including neurologic status, performance status, extent of spinal disease, stability of the spine, extra-spinal disease status, and life expectancy. Patients with spinal instability should be evaluated for surgical intervention. Research studies are needed that evaluate the combination or sequencing of localized therapies with systemic therapies including chemotherapy, hormonal therapy (HT), osteoclast inhibitors (OI), and radiopharmaceuticals. The roles of stereotactic body radiation therapy (SBRT) in the management of spinal oligometastasis, radioresistant spinal metastasis, and previously irradiated but progressive spinal metastasis are emerging, but more research is needed to validate the findings from retrospective studies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140115/1/jpm.2012.0376.pd