| 1. |
- Apponi, A., et al.
(författare)
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Heisenberg's uncertainty principle in the PTOLEMY project : A theory update
- 2022
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 106:5
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the consequences of the quantum uncertainty on the spectrum of the electron emitted by the beta-processes of a tritium atom bound to a graphene sheet. We analyze quantitatively the issue recently raised by Cheipesh, Cheianov, and Boyarsky [Phys. Rev. D 104, 116004 (2021)], and discuss the relevant timescales and the degrees of freedom that can contribute to the intrinsic spread in the electron energy. We perform careful calculations of the potential between tritium and graphene with different coverages and geometries. With this at hand, we propose possible avenues to mitigate the effect of the quantum uncertainty.
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| 2. |
- Apponi, A., et al.
(författare)
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Implementation and optimization of the PTOLEMY transverse drift electromagnetic filter
- 2022
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Ingår i: Journal of Instrumentation. - : IOP Publishing Ltd. - 1748-0221. ; 17:5
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Tidskriftsartikel (refereegranskat)abstract
- The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium beta-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter for electrons with a known pitch angle. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-well design to simultaneously drain the parallel and transverse kinetic energies throughout the length of the filter. These optimizations are shown, in simulation, to achieve low-energy electron transport from a 1 T iron core (or 3 T superconducting) starting field with initial kinetic energy of 18.6 keV drained to < 10 eV (< 1 eV) in about 80 cm. This result for low field operation paves the way for the first demonstrator of the PTOLEMY spectrometer for measurement of electrons near the tritium endpoint to be constructed at the Gran Sasso National Laboratory (LNGS) in Italy.
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| 3. |
- Kochar, Bharati, et al.
(författare)
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Prevalence and Implications of Frailty in Older Adults With Incident Inflammatory Bowel Diseases : A Nationwide Cohort Study
- 2022
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier. - 1542-3565 .- 1542-7714. ; 20:10, s. 2358-2365
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: We aimed to compare the risk of frailty in older adults with incident inflammatory bowel disease (IBD) and matched non-IBD comparators and assess the association between frailty and future hospitalizations and mortality.Methods: In a cohort of patients with incident IBD ≥60 years of age from 2007 to 2016 in Sweden identified using nationwide registers, we defined frailty using Hospital Frailty Risk Score. We compared prevalence of frailty in patients with IBD with age, sex, place of residency– and calendar year–matched population comparators. In the IBD cohort, we used Cox proportional hazards modeling to examine the associations between frailty risk and hospitalizations or mortality.Results: We identified 10,590 patients with IBD, 52% female with a mean age of 71 years of age, matched to 103,398 population-based comparators. Among patients with IBD, 39% had no risk for frailty, 49% had low risk for frailty, and 12% had higher risk for frailty. Mean Hospital Frailty Risk Score was 1.9 in IBD and 0.9 in matched comparators (P < .01). Older adults with IBD at higher risk for frailty had a 20% greater risk for mortality at 3 years compared with those who were not frail. Compared with nonfrail older patients with IBD, patients at higher risk for frailty had increased mortality (hazard ratio [HR], 3.22, 95% confidence interval [CI], 2.86–3.61), all-cause hospitalization (HR, 2.42; 95% CI, 2.24–2.61), and IBD-related hospitalization (HR, 1.50; 95% CI, 1.35–1.66). These associations were not attenuated after adjusting for comorbidities.Conclusions: Frailty is more prevalent in older adults with IBD than in matched comparators. Among older patients with IBD, frailty is associated with increased risk for hospitalizations and mortality.
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