| 1. |
- Gjestvang, D., et al.
(författare)
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Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments
- 2023
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 108:6
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Tidskriftsartikel (refereegranskat)abstract
- The population of isomeric states in the prompt decay of fission fragments-so-called isomeric yield ratios (IYRs)-is known to be sensitive to the angular momentum J that the fragment emerged with, and may therefore contain valuable information on the mechanism behind the fission process. In this work, we investigate how changes in the fissioning system impact the measured IYRs of fission fragments to learn more about what parameters affect angular momentum generation. To enable this, a new technique for measuring IYRs is first demonstrated. It is based on the time of arrival of discrete gamma rays, and has the advantage that it enables the study of the IYR as a function of properties of the partner nucleus. This technique is used to extract the IYR of 134Te, strongly populated in actinide fission, from the three different fissioning systems: 232Th(n, f), 238U(n, f), at two different neutron energies, as well as 252Cf(sf). The impacts of changing the fissioning system, the compound nuclear excitation energy, the minimum J of the binary partner, and the number of neutrons emitted on the IYR of 134Te are determined. The decay code TALYS is used in combination with the fission simulation code FREYA to calculate the primary fragment angular momentum from the IYR. We find that the IYR of 134Te has a slope of 0.004 +/- 0.002 with increase in compound nucleus (CN) mass. When investigating the impact on the IYR of increased CN excitation energy, we find no change with an energy increase similar to the difference between thermal and fast fission. By varying the mass of the partner fragment emerging with 134Te, it is revealed that the IYR of 134Te is independent of the total amount of prompt neutrons emitted from the fragment pair. This indicates that neutrons carry minimal angular momentum away from the fission fragments. Comparisons with the FREYA+TALYS simulations reveal that the average angular momentum in 134Te following 238U(n, f) is 6.0 h over bar . This is not consistent with the value deduced from recent CGMF calculations. Finally, the IYR sensitivity to the angular momentum of the primary fragment is discussed. These results are not only important to help understanding the underlying mechanism in nuclear fission, but can also be used to constrain and benchmark fission models, and are relevant to the gamma -ray heating problem of reactors.
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| 2. |
- Wimmer, K., et al.
(författare)
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Isomeric states in neutron-rich nuclei near N=40
- 2021
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Ingår i: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 104:1
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Tidskriftsartikel (refereegranskat)abstract
- Neutron-rich nuclei in the vicinity of the N = 40 island of inversion are characterized by shell evolution and exhibit deformed ground states. In several nuclei isomeric states have been observed and attributed to excitations to the intruder neutron 1g(9/2) orbital. In the present paper we searched for isomeric states in nuclei around N = 40, Z = 22 produced by projectile fragmentation at the Radioactive Isotope Beam Factory. Delayed. rays were detected by the Euroball RIKEN Cluster Array germanium detector array gamma High statistics data allowed for an updated decay scheme of V-60. The lifetime of an isomeric state in V-64 was measured for the first time in the present experiment. A previously unobserved isomeric state was discovered in Sc-58. The measured lifetime suggests a parity changing transition, originating from an odd number of neutrons in the 1g(9/2) orbital. The nature of the isomeric state in Sc-58 is, thus, different from isomers in the less exotic V and Sc nuclei.
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| 3. |
- Browne, F., et al.
(författare)
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Pairing Forces Govern Population of Doubly Magic Ca-54 from Direct Reactions
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 126:25
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Tidskriftsartikel (refereegranskat)abstract
- Direct proton-knockout reactions of Sc-55 at similar to 220 MeV/nucleon were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca-54 were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological intemucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors, which describe the wave function overlap of the Sc-55 ground state with states in Ca-54. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc-55, valence proton removals populated predominantly the ground state of Ca-54. This counterintuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
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| 4. |
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| 5. |
- Grossi, G, et al.
(författare)
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Alcohol Use among Swedish Patients with Stress-Induced Exhaustion Disorder, and Its Relation to Anxiety, Depression, and Health-Related Quality of Life
- 2022
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Ingår i: INTERNATIONAL JOURNAL OF MENTAL HEALTH AND ADDICTION. - : Springer Science and Business Media LLC. - 1557-1874 .- 1557-1882. ; 20:4, s. 2180-2193
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Harmful drinking may be a cause and an effect of psychological distress, and compromises the effects of treatment for psychiatric conditions. There is a paucity of studies investigating patterns of alcohol consumption among patients with stress-induced exhaustion disorder (SED). The aims of this investigation were (1) to assess the prevalence of self-rated hazardous drinking in a sample of 808 Swedish patients with SED (mean age 43 ± 9 years, 84% women), and (2) to investigate differences in sociodemographic variables, psychological symptoms, health-related quality of life, and sleep variables between patients with different drinking patterns The design was cross-sectional and data were collected with questionnaires at pre-treatment. Twelve percent of female and 13% of male patients reported Alcohol Use Disorder Identification Test (AUDIT) scores indicating hazardous drinking. Female patients with hazardous drinking reported higher levels of anxiety and depression and lower mental wellbeing, than other women. Female patients reporting no drinking reported poorer physical function and more pain, than other women. No differences were seen between male patients with different drinking patterns. Although patients with SED report a lower frequency of harmful drinking than other psychiatric samples, alcohol consumption needs to be addressed in the assessment and treatment of this condition.
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| 6. |
- Soderstrom, HK, et al.
(författare)
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Cohort profile: a nationwide population-based retrospective assessment of oesophageal cancer in the Finnish National Esophago-Gastric Cancer Cohort (FINEGO)
- 2020
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 10:10, s. e039575-
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Tidskriftsartikel (refereegranskat)abstract
- The Finnish National Esophago-Gastric Cancer Cohort (FINEGO) was established to combine the available registry data with detailed patient information to form a comprehensive, retrospective, population-based research platform of surgically treated oesophageal and gastric cancer in Finland. This cohort profile describes the 2045 surgically treated patients with oesophageal cancer included in the FINEGO cohort.ParticipantsRegistry data were collected from the National Cancer, Patient, Education and Death Registries from 1 January 1987 to 31 December 2016. All patients over 18 years of age, who had either curative surgery, palliative surgery or salvage surgery for primary cancer in the oesophagus are included in this study.Findings to date2045 patients had surgery for oesophageal cancer in the selected time period. 67.2% were man, and the majority had only minor comorbidities. The proportions of adenocarcinomas and squamous cell carcinomas were 43.1% and 44.4%, respectively, and 12.5% had other or missing histology. Only about 23% of patients received neoadjuvant therapy. Oesophagectomy was the treatment of choice and most patients were treated at low-volume centres, but median annual hospital volume increased over time. Median overall survival was 23 months, 5-year survival for all patients in the cohort was 32.9% and cancer-specific survival was 36.5%.Future plansEven though Finland only has a population of 5.5 million, surgery for oesophageal carcinoma has not been centralised and therefore previously reported results have mostly been small, single-centre cohorts. Because of FINEGO, we now have a population-based, unselected cohort of surgically treated patients, enabling research on national trends over time regarding oesophageal cancer, including patient characteristics, tumour histology, stage and neoadjuvant treatment, surgical techniques, hospital volumes and patient mortality. Data collection is ongoing, and the cohort will be expanded to include more detailed data from patient records and national biobanks.
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| 7. |
- Ventus, D, et al.
(författare)
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Vibrator-Assisted Start-Stop Exercises Improve Premature Ejaculation Symptoms: A Randomized Controlled Trial
- 2020
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Ingår i: Archives of sexual behavior. - : Springer Science and Business Media LLC. - 1573-2800 .- 0004-0002. ; 49:5, s. 1559-1573
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Tidskriftsartikel (refereegranskat)abstract
- Premature ejaculation (PE) is associated with decreased quality of life, lower confidence and self-esteem, and higher levels of depression, anxiety, and interpersonal difficulties. Here we investigated the effectiveness of vibrator-assisted start–stop exercises for treatment of PE, and whether the treatment effect could be enhanced by an additional psychobehavioral intervention. Fifty participants with a mean age of 41.7 years were included and randomized into two treatment groups and a waiting list control group. Participants were instructed to perform start–stop exercises while stimulating the penis with a purpose-made vibrator, 3 times a week for 6 weeks. Additionally, participants in one of the treatment groups received additional psychoeducation and performed mindfulness meditation-based body scan exercises three times a week. Data were gathered through online questionnaires before and after treatment, as well as 3 and 6 months after treatment. The interventions reduced PE symptoms with large effect sizes (partial η2 = .20 across the three groups, d [95% CI] = 1.05 [.27, 1.82] and 1.07 [.32, 1.82] for treatment groups compared to waiting list control group). The additional psychobehavioral intervention did not further reduce PE symptoms, but did decrease PE-associated negative symptoms such as levels of sexual distress, anxiety, and depression. No side effects were reported. Vibrator-assisted start–stop exercises can be offered as an adequate treatment option for PE.
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