153 research outputs found
Gas Geochemistry and Fractionation Processes in Florina Basin, Greece
Florina Basin is located in northern Greece, close to Mount Voras where the volcanic activity of Late Messinian age began. In the area, many CO2-rich gas emissions are present as a bubbling free-phase in groundwater (both springs and wells) and soil gases. Volcanism along with the geological and geodynamic regime of the basin, created the ideal conditions for CO2 accumulation in vertically stacked reservoirs. One of these, industrially exploited by the company Air Liquide Greece, produces 30,000 t/a of CO2. Results show that CO2 concentrations in the gases of Florina can arrive up to 99.8% and are mostly above 90%. Moreover, C-isotope composition (-2.1 to + 0.3 h vs. VPDB) indicates a mixed mantle-limestone origin for CO2, while He isotope composition (R/RA from 0.21 to 1.20) shows a prevailing crustal origin with an up to 15% mantle contribution. Helium and methane, with concentrations spanning over three orders of magnitude, show a positive correlation and a consequent high variability of He/CO2 and CH4/CO2 ratios. This variability can be attributed to the interaction of the uprising gases with groundwater that chemically fractionates them due to their different solubility. Based on the CO2, CH4 and He concentrations, gas samples collected in the basin can be divided in 3 groups: a) deep reservoir gases, b) enriched in less soluble gases and c) depleted in less soluble gases. The first group consists of gas samples collected at the Air Liquide extraction wells, which tap a 300m deep reservoir. This group can be considered as the least affected by fractionation processes due to interaction with groundwater. The gases of the second group due to their interaction with shallower unsaturated aquifers, become progressively enriched in less soluble gases (He and CH4). Finally, the third group represents residual gas phases after extensive degassing of the groundwater during its hydrological pathway
Complete genome sequence of community-associated methicillin-resistant Staphylococcus aureus Sequence type 1, SCC mec IV[2B], isolated in the 1990s from northern Western Australia
Sequence type 1 (ST1) methicillin-resistant Staphylococcus aureus (MRSA) SCCmec IV[2B] has become one of the most common community-associated MRSA clones in Australia. We report the complete genome sequence of one of the earliest isolated Australian S. aureus ST1-MRSA-IV strains, WBG8287, isolated from an Indigenous Australian patient living in the remote Kimberley region of Western Australia
Islands of shape coexistence: theoretical predictions and experimental evidence
Parameter-free theoretical predictions based on a dual shell mechanism within
the proxy-SU(3) symmetry of atomic nuclei, as well as covariant density
functional theory calculations using the DDME2 functional indicate that shape
coexistence (SC) based on the particle-hole excitation mechanism cannot occur
everywhere on the nuclear chart, but is restricted on islands lying within
regions of 7-8, 17-20, 34-40, 59-70, 96-112, 146-168 protons or neutrons.
Systematics of data for even-even nuclei possessing K=0 (beta) and K=2 (gamma)
bands support the existence of these islands, on which shape coexistence
appears whenever the K=0 bandhead 0_2^+ and the first excited state of the
ground state band 2_1^+ lie close in energy, with nuclei characterized by 0_2^+
lying below the 2_1^+ found in the center of these islands. In addition a
simple theoretical mechanism leading to multiple shape coexistence is briefly
discussed.Comment: 14 pages, 3 tables, 5 figure
Complete genome sequences of three of the earliest community-associated methicillin-resistant Staphylococcus aureus strains isolated in remote Western Australia
Initially reported in Western Australia in the 1980s, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a major cause of S. aureus infections globally. We report the complete genome sequences of three of the earliest CA-MRSA strains isolated from remote Australian Indigenous communities in the Kimberley region of Western Australia
Why nuclear forces favor the highest weight irreducible representations of the fermionic SU(3) symmetry
The consequences of the attractive, short-range nucleon-nucleon (NN)
interaction on the wave functions of the Elliott SU(3) and the proxy-SU(3)
symmetry are discussed. The NN interaction favors the most symmetric spatial
SU(3) irreducible representation, which corresponds to the maximal spatial
overlap among the fermions. The percentage of the symmetric components out of
the total in an SU(3) wave function is introduced, through which it is found,
that no SU(3) irrep is more symmetric than the highest weight irrep for a
certain number of valence particles in a three dimensional, isotropic, harmonic
oscillator shell. The consideration of the highest weight irreps in nuclei and
in alkali metal clusters, leads to the prediction of a prolate to oblate shape
transition beyond the mid-shell region.Comment: 16 pages, 1 figure, 10 table
The islands of shape coexistence within the Elliott and the proxy-SU(3) Models
A novel dual-shell mechanism for the phenomenon of shape coexistence in
nuclei within the Elliott SU(3) and the proxy-SU(3) symmetry is proposed for
all mass regions. It is supposed, that shape coexistence is activated by large
quadrupole-quadrupole interaction and involves the interchange among the
spin-orbit (SO) like shells within nucleon numbers 6-14, 14-28, 28-50, 50-82,
82-126, 126-184, which are being described by the proxy-SU(3) symmetry, and the
harmonic oscillator (HO) shells within nucleon numbers 2-8, 8-20, 20-40, 40-70,
70-112, 112-168 of the Elliott SU(3) symmetry. The outcome is, that shape
coexistence may occur in certain islands on the nuclear map. The dual-shell
mechanism predicts without any free parameters, that nuclei with proton number
(Z) or neutron number (N) between 7-8, 17-20, 34-40, 59-70, 96-112, 146-168 are
possible candidates for shape coexistence. In the light nuclei the nucleons
flip from the HO shell to the neighboring SO-like shell, which means, that
particle excitations occur. For this mass region, the predicted islands of
shape coexistence, coincide with the islands of inversion. But in medium mass
and heavy nuclei, in which the nucleons inhabit the SO-like shells, shape
coexistence is accompanied by a merging of the SO-like shell with the open HO
shell. The shell merging can be accomplished by the outer product of the SU(3)
irreps of the two shells and represents the unification of the HO shell with
the SO-like shell.Comment: 31 pages, 25 figures, 4 table
Comparison of Correction Techniques for the Spill in Effect in Emission Tomography
In positron emission tomography (PET) imaging, accurate clinical assessment is often affected by the partial volume effect (PVE) leading to overestimation (spill-in) or underestimation (spill-out) of activity in various small regions. The spill-in correction, in particular, can be very challenging when the target region is close to a hot background region. Therefore, this study evaluates and compares the performance of various recently developed spill-in correction techniques, namely: background correction (BC), local projection (LP), and hybrid kernelized (HKEM) methods. We used a simulated digital phantom and 18F-NaF PET data of three patients with abdominal aortic aneurysms (AAA) acquired with Siemens Biograph mMRTM and mCTTM scanners respectively. Region of Interest (ROI) analysis was performed and the extracted SUVmean, SUVmax and target-to-background ratio (TBR) scores were compared. Results showed substantial spill-in effects from hot regions to targeted regions, which are more prominent in small structures. The phantom experiment demonstrated the feasibility of spill-in correction with all methods. For the patient data, large differences in SUVmean, SUVmax and TBRmax scores were observed between the ROIs drawn over the entire aneurysm and ROIs excluding some regions close to the bone. Overall, BC yielded the best performance in spill-in correction in both phantom and patient studies
European breast surgical oncology certification theoretical and practical knowledge curriculum 2020
The Breast Surgery theoretical and practical knowledge curriculum comprehensively describes the knowledge and skills expected of a fully trained surgeon practicing in the European Union and European Economic Area (EEA). It forms part of a range of factors that contribute to the delivery of high quality cancer care. It has been developed by a panel of experts from across Europe and has been validated by professional breast surgery societies in Europe. The curriculum maps closely to the syllabus of the Union of European Medical Specialists (UEMS) Breast Surgery Exam, the UK FRCS (breast specialist interest) curriculum and other professional standards across Europe and globally (USA Society of Surgical Oncology, SSO). It is envisioned that this will serve as the basis for breast surgery training, examination and accreditation across Europe to harmonise and raise standards as breast surgery develops as a separate discipline from its parent specialties (general surgery, gynaecology, surgical oncology and plastic surgery).
The curriculum is not static but will be revised and updated by the curriculum development group of the European Breast Surgical Oncology Certification group (BRESO) every 2 years
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