115 research outputs found
Unified description of fission in fusion and spallation reactions
We present a statistical-model description of fission, in the framework of
compound-nucleus decay, which is found to simultaneously reproduce data from
both heavy-ion-induced fusion reactions and proton-induced spallation reactions
at around 1 GeV. For the spallation reactions, the initial compound-nucleus
population is predicted by the Li\`{e}ge Intranuclear Cascade Model. We are
able to reproduce experimental fission probabilities and fission-fragment mass
distributions in both reactions types with the same parameter sets. However, no
unique parameter set was obtained for the fission probability. The introduction
of fission transients can be offset by an increase of the ratio of
level-density parameters for the saddle-point and ground-state configurations.
Changes to the finite-range fission barriers could be offset by a scaling of
the Bohr-Wheeler decay width as predicted by Kramers. The parameter sets
presented allow accurate prediction of fission probabilities for excitation
energies up to 300 MeV and spins up to 60 \hbar.Comment: 16 pages, 20 figures. Submitted to Phys. Rev.
Constraining statistical-model parameters using fusion and spallation reactions
Abstract The de-excitation of compound nuclei has been successfully described for several decades by means of statistical models. However, such models involve a large number of free parameters and ingredients that are often underconstrained by experimental data. We show how the degeneracy of the model ingredients can be partially lifted by studying different entrance channels for de-excitation, which populate different regions of the parameter space of the compound nucleus. Fusion reactions, in particular, play an important role in this strategy because they fix three out of four of the compound-nucleus parameters (mass, charge and total excitation energy). The present work focuses on fission and intermediate-mass-fragment emission cross sections. We prove how equivalent parameter sets for fusion-fission reactions can be resolved using another entrance channel, namely spallation reactions. Intermediate-mass-fragment emission can be constrained in a similar way. An interpretation of the best-fit IMF barriers in terms of the Wigner energies of the nascent fragments is discussed
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Individualized decision aid for diverse women with lupus nephritis (IDEA-WON): A randomized controlled trial.
BackgroundTreatment decision-making regarding immunosuppressive therapy is challenging for individuals with lupus. We assessed the effectiveness of a decision aid for immunosuppressive therapy in lupus nephritis.Methods and findingsIn a United States multicenter, open-label, randomized controlled trial (RCT), adult women with lupus nephritis, mostly from racial/ethnic minority backgrounds with low socioeconomic status (SES), seen in in- or outpatient settings, were randomized to an individualized, culturally tailored, computerized decision aid versus American College of Rheumatology (ACR) lupus pamphlet (1:1 ratio), using computer-generated randomization. We hypothesized that the co-primary outcomes of decisional conflict and informed choice regarding immunosuppressive medications would improve more in the decision aid group. Of 301 randomized women, 298 were analyzed; 47% were African-American, 26% Hispanic, and 15% white. Mean age (standard deviation [SD]) was 37 (12) years, 57% had annual income of <$40,000, and 36% had a high school education or less. Compared with the provision of the ACR lupus pamphlet (n = 147), participants randomized to the decision aid (n = 151) had (1) a clinically meaningful and statistically significant reduction in decisional conflict, 21.8 (standard error [SE], 2.5) versus 12.7 (SE, 2.0; p = 0.005) and (2) no difference in informed choice in the main analysis, 41% versus 31% (p = 0.08), but clinically meaningful and statistically significant difference in sensitivity analysis (net values for immunosuppressives positive [in favor] versus negative [against]), 50% versus 35% (p = 0.006). Unresolved decisional conflict was lower in the decision aid versus pamphlet groups, 22% versus 44% (p < 0.001). Significantly more patients in the decision aid versus pamphlet group rated information to be excellent for understanding lupus nephritis (49% versus 33%), risk factors (43% versus 27%), medication options (50% versus 33%; p ≤ 0.003 for all); and the ease of use of materials was higher in the decision aid versus pamphlet groups (51% versus 38%; p = 0.006). Key study limitations were the exclusion of men, short follow-up, and the lack of clinical outcomes, including medication adherence.ConclusionsAn individualized decision aid was more effective than usual care in reducing decisional conflict for choice of immunosuppressive medications in women with lupus nephritis.Trial registrationClinicaltrials.gov, NCT02319525
Increased phage resistance through lysogenic conversion accompanying emergence of monophasic Salmonella Typhimurium ST34 pandemic strain
Salmonella enterica serovar Typhimurium (S. Typhimurium) comprises a group of closely related human and animal pathogens that account for a large proportion of all Salmonella infections globally. The epidemiological record of S. Typhimurium in Europe is characterized by successive waves of dominant clones, each prevailing for approximately 10–15 years before replacement. Succession of epidemic clones may represent a moving target for interventions aimed at controlling the spread and impact of this pathogen on human and animal health. Here, we investigate the relationship of phage sensitivity and population structure of S. Typhimurium using data from the Anderson phage typing scheme. We observed greater resistance to phage predation of epidemic clones circulating in livestock over the past decades compared to variants with a restricted host range implicating increased resistance to phage in the emergence of epidemic clones of particular importance to human health. Emergence of monophasic S. Typhimurium ST34, the most recent dominant multidrug-resistant clone, was accompanied by increased resistance to phage predation during clonal expansion, in part by the acquisition of the mTmII prophage that may have contributed to the fitness of the strains that replaced ancestors lacking this prophage
The potential of trading activity income to fund third sector organisations operating in deprived areas
In the United Kingdom, as in other countries, Third Sector Organisations (TSOs) have been drawn towards income sources associated with trading activities (Teasdale, 2010), but many remain reliant on grant funding to support such activities (Chell, 2007). Using a multivariate analysis approach and data from the National Survey of Charities and Social Enterprises (NSCSE), it is found that trading activities are used relatively commonly in deprived areas. These organisations are also more likely to attempt to access public sector funds. This suggests policy-makers need to consider the impact of funding cuts on TSOs in the most deprived areas as TSOs are unlikely achieve their objectives without continuing support
Increased phage resistance through lysogenic conversion accompanying emergence of monophasic Salmonella Typhimurium ST34 pandemic strain
Salmonella enterica serovar Typhimurium ( S. Typhimurium) comprises a group of closely related human and animal pathogens that account for a large proportion of all Salmonella infections globally. The epidemiological record of S. Typhimurium in Europe is characterized by successive waves of dominant clones, each prevailing for approximately 10-15 years before replacement. Succession of epidemic clones may represent a moving target for interventions aimed at controlling the spread and impact of this pathogen on human and animal health. Here, we investigate the relationship of phage sensitivity and population structure of S. Typhimurium using data from the Anderson phage typing scheme. We observed greater resistance to phage predation of epidemic clones circulating in livestock over the past decades compared to variants with a restricted host range implicating increased resistance to phage in the emergence of epidemic clones of particular importance to human health. Emergence of monophasic S. Typhimurium ST34, the most recent dominant multidrug-resistant clone, was accompanied by increased resistance to phage predation during clonal expansion, in part by the acquisition of the mTmII prophage that may have contributed to the fitness of the strains that replaced ancestors lacking this prophage
Continuum spectroscopy with a (10)C beam: Cluster structure and three-body decay
Journals published by the American Physical Society can be found at http://publish.aps.org/Resonance-decay spectroscopy is used to study particle-unbound excited states produced in interactions of E/A=10.7 MeV (10)C on Be and C targets. After inelastic scattering, structures associated with excited states in (10)C were observed at 5.22, 5.29, 6.55, 6.56, 6.57, and 8.4 MeV which decay into the 2p+2 alpha final state. This final state is created via a number of different decay paths, which include prompt and sequential two-proton decay to the ground state of (8)Be, alpha decay to (6)Be(g.s.), and proton decay to the 2.345-MeV state of (9)B. For the sequential two-proton decay states (5.22 and 6.55 MeV), angular correlations between the first two decay axes indicate that the spin of these states are nonzero. For the prompt two-proton decay of the 5.29-MeV state, the three-body correlations between the two protons and the core are intermediate between those measured for ground-state (6)Be and (45)Fe decays. The 6.55- and 6.57-MeV structures are most probably associated with the same level, which has a 14% two-proton decay branch with a strong "diproton" character and a 86% sequential two-proton decay branch. Correlations between the fragments following the three-body decay of the 2.345-MeV state of (9)B can be approximately described by sequential alpha decay to the (5)Li intermediate state. The 8.06- and 9.61-MeV (10)B states that decay into the d+(6)Li(2.186) channel are confirmed. Evidence for cluster structure in (13)N is obtained from a number of excited states that decay into the p+3 alpha exit channel
Correlated two-proton decay from (10)C
Journals published by the American Physical Society can be found at http://publish.aps.org/The decay of (10)C excited states to the 2p + 2 alpha exit channel has been studied using inelastic excitation of a secondary (10)C beam. The decay sequences leading to the 2p + 2 alpha final state are determined for the previously known levels and for a newly found level at E* = 8.4 MeV. A state at E* = 6.57 MeV is shown to undergo two-proton decay to (8)Be(g.s.) with strong p-p correlations consistent with the (1)S phase shift. Based on the lack of such correlations for other two-proton decays, this indicates that the correlations are associated with structure of the parent level
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