13 research outputs found
Nuclear astrophysics with radioactive ions at FAIR
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes
Prevalencia y trascendencia de los hallazgos extracardíacos encontrados en resonancia magnética de corazón
Objetivos: Valorar el número de lesiones incidentales detectadas por resonancia magnética (RM) cardíaca, establecer el porcentaje de hallazgos incluidos en el informe y definir el porcentaje de lesiones extracardíacas con implicancia en el manejo del paciente.
Materiales y métodos: Se revisaron retrospectivamente 918 RM de corazón, realizadas desde mayo de 2006 hasta marzo de 2015, en busca de hallazgos extracardíacos. Estos fueron clasificados en nada/poco relevantes o relevantes, y en relación causa-efecto con la sintomatología cardíaca.
Resultados: Se encontraron 271 hallazgos extracardíacos. El 35,7% resultó relevante y el 18,8% tenía una relación de causa-efecto con la sintomatología cardíaca. Los hallazgos extracardíacos relevantes fueron informados en el 58,4% de los casos y los poco/nada relevantes en el 26,6%.
Discusión: Diferentes muestras poblacionales y protocolos de RM cardíaca pueden condicionar los porcentajes de los hallazgos extracardíacos detectados. Además, el análisis de estas imágenes tiene peculiaridades que requieren conocimiento y entrenamiento para una correcta valoración.
Conclusión: Se detectaron hallazgos extracardíacos de diversa relevancia en un 26,4% de los pacientes. Analizar estos hallazgos y establecer su valoración es parte fundamental del informe radiológico de la RM cardíaca
Impact of Most Recent Total Absorption Gamma-ray Spectroscopy Data of Fission Fragments on Reactor Antineutrino Spectra and Comparison with the Daya Bay Results
International audienceThe accurate determination of reactor antineutrino spectra is still a challenge. In 2017 the Daya Bay experiment has measured the evolution of the antineutrino flux with the fuel content of the reactor core. The observed deficit of the detected flux compared with the predictions of the conversion model was almost totally explained by the data arising from the fissions of 235U while the part dominated by the fission of 239Pu was in good agreement with the conversion model. The TAGS collaboration has carried out two experimental campaigns during the last decade at the JYFLTRAP of Jyväskylä (Finland) measuring a large set of data in order to improve the quality of the predictions of our summation method. These measurements allow the correction of the nuclear data for the Pandemonium effect, thus making an important contribution to calculating the antineutrino spectra. The impact of these ten years of measurement from our collaboration on the predicted antineutrino energy spectrum and flux are shown using our summation calculations. The results are compared with the Daya Bay measurements showing the best agreement in shape (in the antineutrino energy range 2 to 5 MeV) and in flux obtained so far with a model. The flux deficit observed by Daya Bay with respect to the summation method is now reduced to 1.9% leaving little room for the reactor anomaly. The shape anomaly between 5 and 7 MeV in antineutrino energy is still observed and remains unexplained
Updated Summation Model: An Improved Agreement with the Daya Bay Antineutrino Fluxes
International audienceA new summation method model of the reactor antineutrino energy spectrum is presented. It is updated with the most recent evaluated decay databases and with our total absorption gamma-ray spectroscopy measurements performed during the last decade. For the first time, the spectral measurements from the Daya Bay experiment are compared with the antineutrino energy spectrum computed with the updated summation method without any renormalization. The results exhibit a better agreement than is obtained with the Huber-Mueller model in the 2–5 MeV range, the region that dominates the detected flux. A systematic trend is found in which the antineutrino flux computed with the summation model decreases with the inclusion of more pandemonium-free data. The calculated flux obtained now lies only 1.9% above that detected in the Daya Bay experiment, a value that may be reduced with forthcoming new pandemonium-free data, leaving less room for a reactor anomaly. Eventually, the new predictions of individual antineutrino spectra for the U235, Pu239, Pu241, and U238 are used to compute the dependence of the reactor antineutrino spectral shape on the fission fractions
Persistent JC virus (JCV) infection is demonstrated by continuous shedding of the same JCV strains
The pressure compensation technology of deep-sea sampling based on the real gas state equation
Nuclear astrophysics with radioactive ions at FAIR
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.Conference Paper</p
Nuclear astrophysics with radioactive ions at FAIR
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.Conference Paper</p