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| 2. |
- 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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| 3. |
- 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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| 5. |
- Sardu, C, et al.
(författare)
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Endothelial Dysfunction Drives CRTd Outcome at 1-Year Follow-Up: A Novel Role as Biomarker for miR-130a-5p
- 2023
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Ingår i: International journal of molecular sciences. - : MDPI AG. - 1422-0067. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial dysfunction (ED) causes worse prognoses in heart failure (HF) patients treated with cardiac resynchronization therapy (CRTd). ED triggers the downregulation of microRNA-130 (miR-130a-5p), which targets endothelin-1 (ET-1). Thus, we evaluated ED and the response to CRTd by assessing miR-130a-5p and ET-1 serum levels. We designed a prospective multi-center study with a 1-year follow-up to evaluate ED, ET-1, and miR-130a-5p in CRTd patients with ED (ED-CRTd) vs. patients without ED (NED-CRTd). Clinical outcomes were CRTd response, HF hospitalization, cardiac death, and all-cause death. At 1-year follow-up, NED-CRTd (n = 541) vs. ED-CRTd (n = 326) patients showed better clinical statuses, lower serum values of B type natriuretic peptide (BNP: 266.25 ± 10.8 vs. 297.43 ± 16.22 pg/mL; p < 0.05) and ET-1 (4.57 ± 0.17 vs. 5.41 ± 0.24 pmol/L; p < 0.05), and higher values of miR-130a-5p (0.51 ± 0.029 vs. 0.41 ± 0.034 A.U; p < 0.05). Compared with NED-CRTd patients, ED-CRTd patients were less likely to be CRTd responders (189 (58%) vs. 380 (70.2%); p < 0.05) and had higher rates of HF hospitalization (115 (35.3%) vs. 154 (28.5%); p < 0.05) and cardiac deaths (30 (9.2%) vs. 21 (3.9%); p < 0.05). Higher miR-130a-5p levels (HR 1.490, CI 95% [1.014–2.188]) significantly predicted CRTd response; the presence of hypertension (HR 0.818, CI 95% [0.669–0.999]), and displaying higher levels of ET-1 (HR 0.859, CI 98% [0.839–0.979]), lymphocytes (HR 0.820, CI 95% [0.758–0.987]), LVEF (HR 0.876, CI 95% [0.760–0.992]), and ED (HR 0.751, CI 95% [0.624–0.905]) predicted CRTd non-response. Higher serum miR-130a-5p levels (HR 0.332, CI 95% [0.347–0.804]) and use of ARNI (HR 0.319, CI 95% [0.310–0.572]) predicted lower risk of HF hospitalization, whereas hypertension (HR 1.818, CI 95% [1.720–2.907]), higher BNP levels (HR 1.210, CI 95% [1.000–1.401]), and presence of ED (HR 1.905, CI 95% [1.238–2.241]) predicted a higher risk of HF hospitalization. Hence, serum miR-130a-5p could identify different stages of ED and independently predict CRTd response, therefore representing a novel prognostic HF biomarker.
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| 6. |
- Mazzuca, Silvia, et al.
(författare)
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Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism, and ecosystem carbon fluxes
- 2013
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES0609 Seagrasses productivity. From genes to ecosystem management, is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems. During 10 days, 20 researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, and underwater acoustics) gathered at The Station de Recherches Sous-marines et Oceanographiques (STARESO, Corsica) to study together the nearby Posidonia oceanica meadow. STARESO is located in an oligotrophic area classified as pristine site where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, which grows in front of the research station, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.
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| 7. |
- Izzo, M. G., et al.
(författare)
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Rayleigh scattering and disorder-induced mixing of polarizations in amorphous solids at the nanoscale: 1-octyl-3-methylimidazolium chloride glass
- 2020
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Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 102:21
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Tidskriftsartikel (refereegranskat)abstract
- Acousticlike excitations in topologically disordered media at mesocale/nanoscale present anomalous features with respect to the Debye's theory. The so-called Rayleigh scattering manifests in a strong increase of the attenuation of the acousticlike excitations and a softening of the phase velocity with respect to its continuum limit value. Mean field models developed in the random media theory framework can successfully predict the occurrence, at the proper length scale, of Rayleigh scattering. The overall attenuation in the Rayleigh region is, however, underestimated. In the framework of random media theory we developed an analytical model, which permits a quantitative description of the acousticlike excitations in topological glasses in the whole first pseudo-Brillouin zone. The underestimation of the Rayleigh scattering is avoided and, importantly, the model allows to account also for the polarization properties of the acousticlike excitations. In a three-dimensional medium an acoustic wave is characterized by its phase velocity, intensity, and polarization. Rayleigh scattering emphasizes how the topological disorder affects the first two properties. The topological disorder is, however, expected to influence also the third one. In common with the Rayleigh scattering, hallmarks possibly related to the mixing of polarizations have been traced in different classes of amorphous solids at nanoscale. The quantitative theoretical approach developed permits to demonstrate how the mixing of polarizations generates a distinctive feature in the dynamic structure factor of amorphous solids. The modeling capability of the proposed mean field theory is tested on glassy 1-octyl-3-methylimidazolium chloride, whose spatial distribution of the elastic moduli is well assessed and can be experimentally characterized. Contrast between theoretical and experimental features for the selected glass reveals an excellent agreement. The mean field approach we present retains a certain degree of generality and can be possibly extended to different stochastic media or different wave fields.
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| 8. |
- Izzo, Maria G., et al.
(författare)
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The Mixing of Polarizations in the Acoustic Excitations of Disordered Media With Local Isotropy
- 2018
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Ingår i: Frontiers in Physics. - : Frontiers Media SA. - 2296-424X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- An approximate solution of the Dyson equation related to a stochastic Helmholtz equation, which describes the acoustic dynamics of a three-dimensional isotropic random medium with elastic tensor fluctuating in space, is obtained in the framework of the Random Media Theory. The wavevector-dependence of the self-energy is preserved, thus allowing a description of the acoustic dynamics at wavelengths comparable with the size of heterogeneity domains. This in turn permits to quantitatively describe the mixing of longitudinal and transverse dynamics induced by the medium's elastic heterogeneity and occurring at such wavelengths. A functional analysis aimed to attest the mathematical coherence and to define the region of validity in the frequency-wavector plane of the proposed approximate solution is presented, with particular emphasis dedicated to the case of disorder characterized by an exponential decay of the covariance function.
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