| 1. |
- Marinucci, A., et al.
(författare)
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Polarization constraints on the X-ray corona in Seyfert Galaxies : MCG-05-23-16
- 2022
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 516:4, s. 5907-5913
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Tidskriftsartikel (refereegranskat)abstract
- We report on the first observation of a radio-quiet active galactic nucleus (AGN) in polarized X-rays: the Seyfert 1.9 galaxy MCG-05-23-16. This source was pointed at with the Imaging X-ray Polarimetry Explorer (IXPE) starting on 2022 May 14 for a net observing time of 486 ks, simultaneously with XMM-Newton (58 ks) and NuSTAR (83 ks). A polarization degree Π smaller than 4.7 per cent (at the 99 per cent confidence level) is derived in the 2–8 keV energy range, where emission is dominated by the primary component ascribed to the hot corona. The broad-band spectrum, inferred from a simultaneous fit to the IXPE, NuSTAR, and XMM-Newton data, is well reproduced by a power law with photon index Γ = 1.85 ± 0.01 and a high-energy cutoff EC = 120 ± 15 keV. A comparison with Monte Carlo simulations shows that a lamp-post and a conical geometry of the corona are consistent with the observed upper limit, a slab geometry is allowed only if the inclination angle of the system is less than 50°.
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| 2. |
- Volpe, Giovanni, 1979, et al.
(författare)
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Roadmap for optical tweezers
- 2023
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Ingår i: Journal of Physics-Photonics. - : IOP Publishing. - 2515-7647. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects, ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in the life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nano-particle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.
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| 3. |
- Abu-Ghanem, Yasmin, et al.
(författare)
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Should patients with low-risk renal cell carcinoma be followed differently after nephron-sparing surgery vs radical nephrectomy?
- 2021
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Ingår i: BJU International. - : John Wiley & Sons. - 1464-4096 .- 1464-410X. ; 128:3, s. 386-394
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate whether pT1 renal cell carcinoma (RCC) should be followed differently after partial (PN) or radical nephrectomy (RN) based on a retrospective analysis of a multicentre database (RECUR).Subjects: A retrospective study was conducted in 3380 patients treated for nonmetastatic RCC between January 2006 and December 2011 across 15 centres from 10 countries, as part of the RECUR database project. For patients with pT1 clear-cell RCC, patterns of recurrence were compared between RN and PN according to recurrence site. Univariate and multivariate models were used to evaluate the association between surgical approach and recurrence-free survival (RFS) and cancer-specific mortality (CSM).Results: From the database 1995 patients were identified as low-risk patients (pT1, pN0, pNx), of whom 1055 (52.9%) underwent PN. On multivariate analysis, features associated with worse RFS included tumour size (hazard ratio [HR] 1.32, 95% confidence interval [CI] 1.14–1.39; P < 0.001), nuclear grade (HR 2.31, 95% CI 1.73–3.08; P < 0.001), tumour necrosis (HR 1.5, 95% CI 1.03–2.3; P = 0.037), vascular invasion (HR 2.4, 95% CI 1.3–4.4; P = 0.005) and positive surgical margins (HR 4.4, 95% CI 2.3–8.5; P < 0.001). Kaplan–Meier analysis of CSM revealed that the survival of patients with recurrence after PN was significantly better than those with recurrence after RN (P = 0.02). While the above-mentioned risk factors were associated with prognosis, type of surgery alone was not an independent prognostic variable for RFS nor CSM. Limitations include the retrospective nature of the study.Conclusion: Our results showed that follow-up protocols should not rely solely on stage and type of primary surgery. An optimized regimen should also include validated risk factors rather than type of surgery alone to select the best imaging method and to avoid unnecessary imaging. A follow-up of more than 3 years should be considered in patients with pT1 tumours after RN. A novel follow-up strategy is proposed.
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| 4. |
- Capitanio, L., et al.
(författare)
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EREBUS: the EuRopean Extinction BUmp Survey
- 2020
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 50:1, s. 145-158
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Tidskriftsartikel (refereegranskat)abstract
- Dust in the Interstellar Medium (ISM) is intimately linked to the life cycle of stars. Despite being of such fundamental importance to galaxy evolution, the dynamic behaviour and composition of the ISM are not yet fully understood. Observations of reddened Milky Way OB stars have revealed a strong UV extinction feature around 2175 Å and a precipitous extinction rise to the far UV along the lines of sight. Whilst the carrier(s) for this are at present still being debated, multiple laboratory studies suggest carbonate grains to be the key constituent. EREBUS is a mission concept being developed to study the composition of the ISM in both the Milky Way and Local Group Galaxies, primarily by mapping the spatial distribution of the UV extinction features. As these features are sensitive to the dust composition along the line of sight, EREBUS will provide a wealth of information about the spatial distribution and dynamic behaviour of the carrier(s). The mission proposes to deploy a satellite observatory equipped with a coarse UV spectrograph to map the extinction curve variability in the Milky Way in 3 dimensions and in the Local Group in 2 dimensions. In this paper, we discuss the scientific goals for the project, discuss a proposed observation strategy using an iterative process to develop a hierarchical map, and finally outline the instrument requirements and preliminary spacecraft architecture.
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