5 research outputs found
Modeling geographic vaccination strategies for COVID-19 in Norway.
Vaccination was a key intervention in controlling the COVID-19 pandemic globally. In early 2021, Norway faced significant regional variations in COVID-19 incidence and prevalence, with large differences in population density, necessitating efficient vaccine allocation to reduce infections and severe outcomes. This study explored alternative vaccination strategies to minimize health outcomes (infections, hospitalizations, ICU admissions, deaths) by varying regions prioritized, extra doses prioritized, and implementation start time. Using two models (individual-based and meta-population), we simulated COVID-19 transmission during the primary vaccination period in Norway, covering the first 7 months of 2021. We investigated alternative strategies to allocate more vaccine doses to regions with a higher force of infection. We also examined the robustness of our results and highlighted potential structural differences between the two models. Our findings suggest that early vaccine prioritization could reduce COVID-19 related health outcomes by 8% to 20% compared to a baseline strategy without geographic prioritization. For minimizing infections, hospitalizations, or ICU admissions, the best strategy was to initially allocate all available vaccine doses to fewer high-risk municipalities, comprising approximately one-fourth of the population. For minimizing deaths, a moderate level of geographic prioritization, with approximately one-third of the population receiving doubled doses, gave the best outcomes by balancing the trade-off between vaccinating younger people in high-risk areas and older people in low-risk areas. The actual strategy implemented in Norway was a two-step moderate level aimed at maintaining the balance and ensuring ethical considerations and public trust. However, it did not offer significant advantages over the baseline strategy without geographic prioritization. Earlier implementation of geographic prioritization could have more effectively addressed the main wave of infections, substantially reducing the national burden of the pandemic
Complete kinematics reconstruction in the golden cascade
Vi undersøker ein metode, opphavleg foreslått i [1], for å bestemme massane til resonansar og usynlege sluttilstandar i kaskadehenfall, i teoriar utanfor Standardmodellen med ein paritetssymmetri. Vi gjer undersøkinga vår innanfor rammeverket til den Minimale Supersymmetriske Standardmodellen med bevaring av R-paritet. Metoden formulerer massebestemminga som eit optimeringsproblem som kan løysast med numeriske verktøy. I [1] vart det demonstrert med Monte Carlo-simuleringar at metoden har gode utsikter for nøyaktig massebestemming. Vi finn at det er visse problem med metoden og analysen, som leiar til underestimering av feilen. I lys av dette presenterer vi reviderte feilestimat. Vi held fram med å undersøke alternative formuleringar av metoden som kanskje kan løyse problema, og presenterer masseestimat og usikkerheiter for Monte Carlo-analysar av desse alternative formuleringane. Vi undersøker også effektane av jet-rekonstruksjon, og viser at dette er ei viktig kjelde til feil for metoden
A new software implementation of the Oslo method with rigorous statistical uncertainty propagation
The Oslo method comprises a set of analysis techniques designed to extract nuclear level density and average -decay strength function from a set of excitation-energy tagged -ray spectra. Here we present a new software implementation of the entire Oslo method, called OMpy. We provide a summary of the theoretical basis and derive the essential equations used in the Oslo method. In addition to the functionality of the original analysis code, the new implementation includes novel components such as a rigorous method to propagate uncertainties throughout all steps of the Oslo method using a Monte Carlo approach. The resulting level density and -ray strength function have to be normalized to auxiliary data. The normalization is performed simultaneously for both quantities, thus preserving all correlations. The software is verified by the analysis of a synthetic spectrum and compared to the results of the previous implementation, the oslo-method-software
Low-energy enhancement and fluctuations of γ-ray strength functions in 56,57Fe: test of the Brink–Axel hypothesis
Nuclear level densities and γ-ray strength functions of 56,57Fe have been extracted from proton-γ coincidences. A low-energy enhancement in the γ-ray strength functions up to a factor of 30 over common theoretical E1 models is confirmed. Angular distributions of the low-energy enhancement in 57Fe indicate its dipole nature, in agreement with findings for 56Fe. The high statistics and the excellent energy resolution of the large-volume LaBr3(Ce) detectors allowed for a thorough analysis of γ strength as function of excitation energy. Taking into account the presence of strong Porter–Thomas fluctuations, there is no indication of any significant excitation energy dependence in the γ-ray strength function, in support of the generalized Brink–Axel hypothesis.
This research was first published in Journal of Physics G: Nuclear and Particle Physics. © IOP Publishing
Benchmarking the extraction of statistical neutron capture cross sections on short-lived nuclei for applications using the β-Oslo method
Numerous scientific fields including astrophysics, nuclear power, and nuclear forensics require a knowledge of basic nuclear properties for large numbers of short-lived, radioactive isotopes far removed from stable nuclei. Neutron-capture cross sections are one such piece of nuclear data where direct measurements are not possible and theoretical predictions can vary by orders of magnitude. A recently developed indirect technique for inferring neutron capture rates, the β -Oslo method, has been introduced but not compared against a known, directly measured neutron capture cross section. To provide this benchmark, two indirect methods based on β decay and charged-particle reactions were used to extract the nuclear level density and γ -ray strength function of 51 Ti . The nuclear level density and γ -ray strength function from the two data sets were found to be equivalent and were used to extract the neutron capture cross section of 50 Ti which agrees with previous direct measurements at high neutron energies. The results demonstrate the validity of the β -Oslo method for extracting neutron capture cross sections of short-lived nuclei and provide a sufficiently small uncertainty to be used in various applications