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589 result(s) for "Gustafsson, F"
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Spectroscopy of short-lived radioactive molecules
Molecular spectroscopy offers opportunities for the exploration of the fundamental laws of nature and the search for new particle physics beyond the standard model 1 – 4 . Radioactive molecules—in which one or more of the atoms possesses a radioactive nucleus—can contain heavy and deformed nuclei, offering high sensitivity for investigating parity- and time-reversal-violation effects 5 , 6 . Radium monofluoride, RaF, is of particular interest because it is predicted to have an electronic structure appropriate for laser cooling 6 , thus paving the way for its use in high-precision spectroscopic studies. Furthermore, the effects of symmetry-violating nuclear moments are strongly enhanced 5 , 7 – 9 in molecules containing octupole-deformed radium isotopes 10 , 11 . However, the study of RaF has been impeded by the lack of stable isotopes of radium. Here we present an experimental approach to studying short-lived radioactive molecules, which allows us to measure molecules with lifetimes of just tens of milliseconds. Energetically low-lying electronic states were measured for different isotopically pure RaF molecules using collinear resonance ionisation at the ISOLDE ion-beam facility at CERN. Our results provide evidence of the existence of a suitable laser-cooling scheme for these molecules and represent a key step towards high-precision studies in these systems. Our findings will enable further studies of short-lived radioactive molecules for fundamental physics research. Measurements of low-energy electronic states of radium monofluoride validate predictions of the use of this short-lived radioactive molecule in exploring fundamental physics and provide evidence of its suitability for laser cooling.
Patisiran Treatment in Patients with Transthyretin Cardiac Amyloidosis
Transthyretin amyloidosis, also called ATTR amyloidosis, is associated with accumulation of ATTR amyloid deposits in the heart and commonly manifests as progressive cardiomyopathy. Patisiran, an RNA interference therapeutic agent, inhibits the production of hepatic transthyretin. In this phase 3, double-blind, randomized trial, we assigned patients with hereditary, also known as variant, or wild-type ATTR cardiac amyloidosis, in a 1:1 ratio, to receive patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks for 12 months. A hierarchical procedure was used to test the primary and three secondary end points. The primary end point was the change from baseline in the distance covered on the 6-minute walk test at 12 months. The first secondary end point was the change from baseline to month 12 in the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS) score (with higher scores indicating better health status). The second secondary end point was a composite of death from any cause, cardiovascular events, and change from baseline in the 6-minute walk test distance over 12 months. The third secondary end point was a composite of death from any cause, hospitalizations for any cause, and urgent heart failure visits over 12 months. A total of 360 patients were randomly assigned to receive patisiran (181 patients) or placebo (179 patients). At month 12, the decline in the 6-minute walk distance was lower in the patisiran group than in the placebo group (Hodges-Lehmann estimate of median difference, 14.69 m; 95% confidence interval [CI], 0.69 to 28.69; P = 0.02); the KCCQ-OS score increased in the patisiran group and declined in the placebo group (least-squares mean difference, 3.7 points; 95% CI, 0.2 to 7.2; P = 0.04). Significant benefits were not observed for the second secondary end point. Infusion-related reactions, arthralgia, and muscle spasms occurred more often among patients in the patisiran group than among those in the placebo group. In this trial, administration of patisiran over a period of 12 months resulted in preserved functional capacity in patients with ATTR cardiac amyloidosis. (Funded by Alnylam Pharmaceuticals; APOLLO-B ClinicalTrials.gov number, NCT03997383.).
Laser spectroscopy of indium Rydberg atom bunches by electric field ionization
This work reports on the application of a novel electric field-ionization setup for high-resolution laser spectroscopy measurements on bunched fast atomic beams in a collinear geometry. In combination with multi-step resonant excitation to Rydberg states using pulsed lasers, the field ionization technique demonstrates increased sensitivity for isotope separation and measurement of atomic parameters over previous non-resonant laser ionization methods. The setup was tested at the Collinear Resonance Ionization Spectroscopy experiment at ISOLDE-CERN to perform high-resolution measurements of transitions in the indium atom from the 5s 2 5d 2 D 5 / 2 and 5s 2 5d 2 D 3 / 2 states to 5s 2 n p  2 P and 5s 2 n f 2 F Rydberg states, up to a principal quantum number of n = 72 . The extracted Rydberg level energies were used to re-evaluate the ionization potential of the indium atom to be 46 , 670.107 ( 4 ) cm - 1 . The nuclear magnetic dipole and nuclear electric quadrupole hyperfine structure constants and level isotope shifts of the 5s 2 5d 2 D 5 / 2 and 5s 2 5d 2 D 3 / 2 states were determined for 113 , 115 In. The results are compared to calculations using relativistic coupled-cluster theory. A good agreement is found with the ionization potential and isotope shifts, while disagreement of hyperfine structure constants indicates an increased importance of electron correlations in these excited atomic states. With the aim of further increasing the detection sensitivity for measurements on exotic isotopes, a systematic study of the field-ionization arrangement implemented in the work was performed at the same time and an improved design was simulated and is presented. The improved design offers increased background suppression independent of the distance from field ionization to ion detection.
Analytic response relativistic coupled-cluster theory: the first application to indium isotope shifts
With increasing demand for accurate calculation of isotope shifts of atomic systems for fundamental and nuclear structure research, an analytic energy derivative approach is presented in the relativistic coupled-cluster (CC) theory framework to determine the atomic field shift and mass shift (MS) factors. This approach allows the determination of expectation values of atomic operators, overcoming fundamental problems that are present in existing atomic physics methods, i.e. it satisfies the Hellmann-Feynman theorem, does not involve any non-terminating series, and is free from choice of any perturbative parameter. As a proof of concept, the developed analytic response relativistic CC theory has been applied to determine MS and field shift factors for different atomic states of indium. High-precision isotope-shift measurements of 104 − 127 In were performed in the 246.8 nm (5p 2P3/2 → 9s 2S1/2) and 246.0 nm (5p 2P1/2 → 8s 2S1/2) transitions to test our theoretical results. An excellent agreement between the theoretical and measured values is found, which is known to be challenging in multi-electron atoms. The calculated atomic factors allowed an accurate determination of the nuclear charge radii of the ground and isomeric states of the 104 − 127 In isotopes, providing an isotone-independent comparison of the absolute charge radii.
Charge radii of exotic potassium isotopes challenge nuclear theory and the magic character of N = 32
Nuclear charge radii are sensitive probes of different aspects of the nucleon–nucleon interaction and the bulk properties of nuclear matter, providing a stringent test and challenge for nuclear theory. Experimental evidence suggested a new magic neutron number at N = 32 (refs. 1–3) in the calcium region, whereas the unexpectedly large increases in the charge radii4,5 open new questions about the evolution of nuclear size in neutron-rich systems. By combining the collinear resonance ionization spectroscopy method with β-decay detection, we were able to extend charge radii measurements of potassium isotopes beyond N = 32. Here we provide a charge radius measurement of 52K. It does not show a signature of magic behaviour at N = 32 in potassium. The results are interpreted with two state-of-the-art nuclear theories. The coupled cluster theory reproduces the odd–even variations in charge radii but not the notable increase beyond N = 28. This rise is well captured by Fayans nuclear density functional theory, which, however, overestimates the odd–even staggering effect in charge radii. These findings highlight our limited understanding of the nuclear size of neutron-rich systems, and expose problems that are present in some of the best current models of nuclear theory.The charge radii of potassium isotopes up to 52K are measured, and show no sign of magicity at 32 neutrons as previously suggested in calcium. The observations are interpreted with coupled cluster and density functional theory calculations.
Levosimendan in Acute and Advanced Heart Failure: an Expert Perspective on Posology and Therapeutic Application
Levosimendan, a calcium sensitizer and potassium channel-opener, is widely appreciated by many specialist heart failure practitioners for its effects on systemic and pulmonary hemodynamics and for the relief of symptoms of acute heart failure. The drug’s impact on mortality in large randomized controlled trials has been inconsistent or inconclusive but, in contrast to conventional inotropes, there have been no indications of worsened survival and some signals of improved heart failure-related quality of life. For this reason, levosimendan has been proposed as a safer inodilator option than traditional agents in settings, such as advanced heart failure. Positive effects of levosimendan on renal function have also been described. At the HEART FAILURE 2018 congress of the Heart Failure Association of the European Society of Cardiology, safe and effective use levosimendan in acute and advanced heart failure was examined in a series of expert tutorials. The proceedings of those tutorials are summarized in this review, with special reference to advanced heart failure and heart failure with concomitant renal dysfunction. Meta-analysis of clinical trials data is supportive of a renal-protective effect of levosimendan, while physiological observations suggest that this effect is exerted at least in part via organ-specific effects that may include selective vasodilation of glomerular afferent arterioles and increased renal blood flow, with no compromise of renal oxygenation. These lines of evidence require further investigation and their clinical significance needs to be evaluated in specifically designed prospective trials.
Electromagnetic properties of indium isotopes illuminate the doubly magic character of 100Sn
Understanding the nuclear properties in the vicinity of 100 Sn, which has been suggested to be the heaviest doubly magic nucleus with proton number Z equal to neutron number N , has been a long-standing challenge for experimental and theoretical nuclear physics. In particular, contradictory experimental evidence exists regarding the role of nuclear collectivity in this region of the nuclear chart. Here, we provide further evidence for the doubly magic character of 100 Sn by measuring the ground-state electromagnetic moments and nuclear charge radii of indium ( Z  = 49) isotopes as N approaches 50 from above using precision laser spectroscopy. Our results span almost the complete range between the two major closed neutron shells at N  = 50 and N  = 82 and reveal parabolic trends as a function of the neutron number, with a clear reduction towards these two closed neutron shells. A detailed comparison between our experimental results and numerical results from two complementary nuclear many-body frameworks (density functional theory and ab initio methods) exposes deficiencies in nuclear models and establishes a benchmark for future theoretical developments. Precision laser spectroscopy of ground-state electromagnetic moments and nuclear charge radii of indium shows that 100 Sn has closed proton and neutron shells. The results serve as a benchmark for future theoretical models.
SDR, EVC, and SDREVC: Limitations and Extensions
Methods for reducing the radius, temperature and space charge of a non-neutral plasma are usually reported for conditions which approximate an ideal Penning Malmberg trap. Here, we show that (i) similar methods are still effective under surprisingly adverse circumstances: we perform strong drive regime (SDR) compression and SDREVC in a strong magnetic mirror field using only 3 out of 4 rotating wall petals. In addition, we demonstrate (ii) an alternative to SDREVC, using e-kick instead of evaporative cooling (EVC) and (iii) an upper limit for how much plasma can be cooled to $T<20\\ \\mathrm {K}$ using EVC. This limit depends on the space charge, not on the number of particles or the plasma density.
Slow positron production and storage for the ASACUSA-Cusp experiment
The ASACUSA (atomic spectroscopy and collisions using slow antiprotons) Cusp experiment requires the production of dense positron plasmas with a high repetition rate to produce a beam of antihydrogen. In this work, details of the positron production apparatus used for the first observation of the antihydrogen beam, and subsequent measurements, are described in detail. This apparatus replaced the previous compact trap design resulting in an improvement in the positron accumulation rate by a factor of $52\\pm 3$.
Excess Risk of Mortality and Hospitalization in Patients with Heart Failure According to Age and Comorbidity – A Nationwide Register Study
Heart failure (HF) is associated with increased risk of death and a hospitalization, but for patients initiating guideline directed medical therapy, it is unknown how high these risks are compared to the general population - and how this may vary depending on age and comorbidity. In this retrospective cohort study, we identified patients diagnosed with HF in the period 2011-2017, surviving the initial 120 days after diagnosis. Patients who were on angiotensin converting enzyme inhibitor (ACEi)/ angiotensin receptor blocker (ARB) and beta-blocker were included and matched to 5 non-HF individuals from the background population each based on age and sex. We assessed the 5-year risk of all-cause death, HF and non-HF hospitalization according to sex and age and baseline comorbidity. We included 35,367 patients with HF and 176,835 matched non-HF individuals. Patients with HF had a five-year excess risk (absolute risk difference) of death of 13% (31% [for HF] - 18% [for non-HF]), of HF hospitalization of 17% and of non-HF hospitalization of 24%. Excess risk of death increased with increasing age, whereas the relative risk decreased - for women in their twenties, the excess risk was 7%, risk ratio 7.2, while the excess risk was 18%, risk ratio 1.5 for women in their eighties. Having HF as a 60-year old man was associated with a five-year risk of death similar to a 75-year old man without HF. Further, HF was associated with an excess risk of non-HF hospitalization, ranging from 8% for patients >85 years to 30% for patients <30 years. Regardless of age, sex and comorbidity, HF was associated with excess risk of mortality and non-HF hospitalizations, but the relative risk ratio diminishes sharply with advancing age, which may influence allocation of resources for medical care across populations.