134 research outputs found
Shell-model half-lives for r-process waiting point nuclei including first-forbidden contributions
We have performed large-scale shell-model calculations of the half-lives and
neutron-branching probabilities of the r-process waiting point nuclei at the
magic neutron numbers N=50, 82, and 126. The calculations include contributions
from allowed Gamow-Teller and first-forbidden transitions. We find good
agreement with the measured half-lives for the N=50 nuclei with charge numbers
Z=28-32 and for the N=82 nuclei 129Ag and 130Cd. The contribution of forbidden
transitions reduce the half-lives of the N=126 waiting point nuclei
significantly, while they have only a small effect on the half-lives of the
N=50 and 82 r-process nuclei.Comment: 14 pages, 17 figures, submitted to Phys. Rev.
Using Photodynamic Therapy to Estimate Effectiveness of Innovative Combined Diclofenac and Tazaroten Therapy of Disseminated Actinic Keratosis
Early diagnosis and therapy of precancerous lesions and malignant tumors belong to the most challenging tasks in modern medicine. Photodynamic diagnosis can help diagnose both precancerous lesions and early carcinoma. Actinic keratosis (AK) is the most common precancerous lesion of the skin. The available data show a high effectiveness of diclofenac in treating multifocal AK. We report a case of a 52-year-old woman who complained of multiple disseminated AK lesions predominantly on the lower limbs and trunk with a significant exacerbation within the last 6 months. Due to the spreading of disease and a high number of AK foci, as well as technical problems with visiting the hospital (PDT Laboratory), photodynamic therapy was not applied. The patient was treated for 2 months with a combination of local administration of 3% diclofenac and 0.1% tazaroten and 3% diclofenac only as a half side (left-right) comparison. The effects of therapy were later clinically evaluated and verified by means of photodynamic diagnosis (PDD) directly after therapy and at a follow-up examination 3 months later. The evaluation of treatment was blinded.Treatment with diclofenac only on the right side of the body resulted in clearing of 55% of all treated lesions, which increased to 60% three months after finishing therapy. On the left side of the body, where combined therapy (diclofenac 2 times daily on uneven dates and diclofenac once a day + tazaroten once a day on even dates) was used, 77.5% pathologic lesions disappeared, but this did not increase at follow up. The treatment of multifocal, disseminated AK is a difficult task and also burdensome for the patient due to side effects like scarring or burning and itching which occur during most therapies. Combined therapy with diclofenac and tazaroten supported by PDD may improve the effects of routine treatment of AK.</p
Time-of-flight mass measurements of neutron-rich chromium isotopes up to N = 40 and implications for the accreted neutron star crust
We present the mass excesses of 59-64Cr, obtained from recent time-of-flight
nuclear mass measurements at the National Superconducting Cyclotron Laboratory
at Michigan State University. The mass of 64Cr is determined for the first
time, with an atomic mass excess of -33.48(44) MeV. We find a significantly
different two-neutron separation energy S2n trend for neutron-rich isotopes of
chromium, removing the previously observed enhancement in binding at N=38.
Additionally, we extend the S2n trend for chromium to N=40, revealing behavior
consistent with the previously identified island of inversion in this region.
We compare our results to state-of-the-art shell-model calculations performed
with a modified Lenzi-Nowacki-Poves-Sieja interaction in the fp shell,
including the g9/2 and d5/2 orbits for the neutron valence space. We employ our
result for the mass of 64Cr in accreted neutron star crust network calculations
and find a reduction in the strength and depth of electron-capture heating from
the A=64 isobaric chain, resulting in a cooler than expected accreted neutron
star crust. This reduced heating is found to be due to the >1-MeV reduction in
binding for 64Cr with respect to values from commonly used global mass models.Comment: Accepted to Physical Review
Large-Scale Self-Consistent Nuclear Mass Calculations
The program of systematic large-scale self-consistent nuclear mass
calculations that is based on the nuclear density functional theory represents
a rich scientific agenda that is closely aligned with the main research
directions in modern nuclear structure and astrophysics, especially the
radioactive nuclear beam physics. The quest for the microscopic understanding
of the phenomenon of nuclear binding represents, in fact, a number of
fundamental and crucial questions of the quantum many-body problem, including
the proper treatment of correlations and dynamics in the presence of symmetry
breaking. Recent advances and open problems in the field of nuclear mass
calculations are presented and discussed.Comment: 21 pages, 5 figures, submitted to International Journal of Mass
Spectrometr
Isomeric excitation energy for In from mass spectrometry reveals constant trend next to doubly magic Sn
The excitation energy of the 1/2 isomer in In at is
measured to be 671(37) keV and the mass uncertainty of the 9/2 ground state
is significantly reduced using the ISOLTRAP mass spectrometer at ISOLDE/CERN.
The measurements exploit a major improvement in the resolution of the
multi-reflection time-of-flight mass spectrometer. The results reveal an
intriguing constancy of the isomer excitation energies in
neutron-deficient indium that persists down to the shell closure, even
when all neutrons are removed from the valence shell. This trend is used to
test large-scale shell model, \textit{ab initio}, and density functional theory
calculations. The models have difficulties describing both the isomer
excitation energies and ground-state electromagnetic moments along the indium
chain.Comment: 13 pages, 4 figure
Identifying and addressing barriers to implementing core electronic health record use metrics for ambulatory care: Virtual consensus conference proceedings
Precise, reliable, valid metrics that are cost-effective and require reasonable implementation time and effort are needed to drive electronic health record (EHR) improvements and decrease EHR burden. Differences exist between research and vendor definitions of metrics. PROCESS: âWe convened three stakeholder groups (health system informatics leaders, EHR vendor representatives, and researchers) in a virtual workshop series to achieve consensus on barriers, solutions, and next steps to implementing the core EHR use metrics in ambulatory care. CONCLUSION: âActionable solutions identified to address core categories of EHR metric implementation challenges include: (1) maintaining broad stakeholder engagement, (2) reaching agreement on standardized measure definitions across vendors, (3) integrating clinician perspectives, and (4) addressing cognitive and EHR burden. Building upon the momentum of this workshop\u27s outputs offers promise for overcoming barriers to implementing EHR use metrics
First g(2+) measurement on neutron-rich 72 Zn, and the high-velocity transient field technique for radioactive heavy-ion beams
The high-velocity transient-field (HVTF) technique was used to measure the g factor of the 2+ state of 72Zn produced as a radioactive beam. The transient-field strength was probed at high velocity in ferromagnetic iron and gadolinium hosts using 76Ge beams. The potential of the HVTF method is demonstrated and the difficulties that need to be overcome for a reliable use of the TF technique with high-Z, high-velocity radioactive beams are revealed. The polarization of K-shell vacancies at high velocity, which shows more than an order of magnitude difference between Z = 20 and Z = 30 is discussed. The g-factor measurement hints at the theoretically predicted transition in the structure of the Zn isotopes near N = 40
Nuclear Structure Towards N=40 60Ca: In-beam gamma-ray Spectroscopy of 58,60Ti
Excited states in the neutron-rich N=38,36 nuclei \nuc{60}{Ti} and
\nuc{58}{Ti} were populated in nucleon-removal reactions from \nuc{61}{V}
projectiles at 90~MeV/nucleon. The \gamma-ray transitions from such states in
these Ti isotopes were detected with the advanced \gamma-ray tracking array
GRETINA and were corrected event-by-event for large Doppler shifts (v/c \sim
0.4) using the \gamma-ray interaction points deduced from online signal
decomposition. The new data indicate that a steep decrease in quadrupole
collectivity occurs when moving from neutron-rich N=36,38 Fe and Cr toward the
Ti and Ca isotones. In fact, \nuc{58,60}{Ti} provide some of the most
neutron-rich benchmarks accessible today for calculations attempting to
determine the structure of the potentially doubly-magic nucleus \nuc{60}{Ca}.Comment: Accepted for publication in Physical Review letter
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