| 461. |
- Gimperlein, H., et al.
(författare)
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On the magnitude function of domains in Euclidean space
- 2021
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Ingår i: American Journal of Mathematics. - : Project Muse. - 0002-9327 .- 1080-6377. ; 143:3, s. 939-967
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Tidskriftsartikel (refereegranskat)abstract
- We study Leinster's notion of magnitude for a compact metric space. For a smooth, compact domain X subset of R2m-1, we find geometric significance in the function M-X(R) = mag(R . X). The function M-X extends from the positive half-line to a meromorphic function in the complex plane. Its poles are generalized scattering resonances. In the semiclassical limit R -> infinity, M-X admits an asymptotic expansion. The three leading terms of M-X at R = +infinity are proportional to the volume, surface area and integral of the mean curvature. In particular, for convex X the leading terms are proportional to the intrinsic volumes, and we obtain an asymptotic variant of the convex magnitude conjecture by Leinster and Willerton, with corrected coefficients.
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| 462. |
- Giuffrida, L., et al.
(författare)
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Manipulation of laser-accelerated proton beam profiles by nanostructured and microstructured targets
- 2017
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Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 20:8, s. 081301-
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured and microstructured thin foils have been fabricated and used experimentally as targets to manipulate the spatial profile of proton bunches accelerated through the interaction with high intensity laser pulses (6 x 1019 W/cm(2)). Monolayers of polystyrene nanospheres were placed on the rear surfaces of thin plastic targets to improve the spatial homogeneity of the accelerated proton beams. Moreover, thin targets with grating structures of various configurations on their rear sides were used tomodify the proton beam divergence. Experimental results are presented, discussed, and supported by 3D particle-in-cell numerical simulations.
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| 463. |
- Giuffrida, L., et al.
(författare)
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Nano and micro structured targets to modulate the spatial profile of laser driven proton beams
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12:3, s. article no C03040 -
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Tidskriftsartikel (refereegranskat)abstract
- Nano and micro structured thin (μ m-scale) foils were designed, fabricated and irradiated with the high intensity laser system operating at LLC (Lund Laser Centre, Sweden) in order to systematically study and improve the main proton beam parameters. Nano-spheres deposited on the front (laser irradiated) surface of a flat Mylar foil enabled a small enhancement of the maximum energy and number of the accelerated protons. Nano-spheres on the rear side allowed to modify the proton beam spatial profile. In particular, with nanospheres deposited on the rear of the target, the proton beam spatial homogeneity was clearly enhanced. Silicon nitride thin foils having micro grating structures (with different step dimensions) on the rear surface were also used as targets to influence the divergence of the proton beam and drastically change its shape through a sort of stretching effect. The target fabrication process used for the different target types is described, and representative experimental results are shown and discussed along with supporting 3D particle-in-cell simulations. © 2017 IOP Publishing Ltd and Sissa Medialab srl.
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| 464. |
- Glad, Camilla A M, 1981, et al.
(författare)
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The GH receptor exon 3 deleted/full-length polymorphism is associated with central adiposity in the general population.
- 2015
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Ingår i: European journal of endocrinology / European Federation of Endocrine Societies. - 1479-683X .- 0804-4643. ; 172:2, s. 123-128
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To test the hypothesis that the growth hormone (GH) receptor (GHR) d3/fl polymorphism influences anthropometry and body composition in the general population. Design and Setting: The Swedish Obese Subjects (SOS) reference study is a cross-sectional population-based study, randomly selected from a population registry. A sub-group of the population-based Malmö Diet and Cancer Study (MDC-CC) was used as a replication cohort. Methods: The SOS reference study comprises 1135 subjects (46.2% men), with an average age of 49.5 yrs. The MDC-CC includes 5451 successfully genotyped subjects (41.5% men), with an average age of 57.5 yrs. GHR d3/fl genotypes were determined using tagSNP rs6873545. Linear regression analyses were used to test for genotype - phenotype associations. Results: In the SOS reference study, subjects homozygous for the d3-GHR weighed approximately four kilos more (p=0.011), had larger waist-to-hip ratio (WHR, p=0.036), waist circumference (p=0.016) and more fat free mass estimated from total body potassium (TBK, p=0.026) than grouped fl/d3 and fl/fl subjects (d3-recessive genetic model). The association with WHR was replicated in the MDC-CC (p=0.002), but not those with other anthropometric traits. Conclusions: In this population-based study the GHR d3/fl polymorphism was found to be of functional relevance and associated with central adiposity, such that subjects homozygous for the d3-GHR showed an increased abdominal obesity.
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| 465. |
- Glasius, M., et al.
(författare)
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Composition and sources of carbonaceous aerosols in Northern Europe during winter
- 2018
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1873-2844 .- 1352-2310. ; 173, s. 127-141
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Tidskriftsartikel (refereegranskat)abstract
- Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14 C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m −3 , whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m −3 . One weekly mean TC concentration as high as 11 μg C m −3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m −3 (Birkenes) to 249 ± 13 ng m −3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4–53 ng m −3 , with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m −3 , between individual sites and samples. The three sites Melpitz, Rotterdam and Cabauw, located closest to source regions in continental Europe, showed very high levels of organosulphates and nitrooxy organosulphates (up to 414 ng m −3 ) during the first two weeks of the study, while low levels ( < 7 ng m −3 ) were found at all sites except Melpitz during the last week. The large variation in organosulphate levels probably reflects differences in the presence of acidic sulphate aerosols, known from laboratory studies to accelerate the formation of these compounds. On average, the ratio of organic sulphate to inorganic sulphate was 1.5 ± 1.0% (range 0.1–3.4%). Latin-hypercube source apportionment techniques identified biomass burning as the major source of OC for all samples at all sites (typically > 40% of TC), while use and combustion of fossil fuels was the second most important source. Furthermore, EC from biomass burning accounted for 7–16% of TC, whereas EC from fossil sources contributed to < 2–23% of TC, of which the highest percentages were observed for low-concentration aerosol samples. Unresolved non-fossil sources (such as cooking and biogenic secondary organic aerosols) did not account for more than 5–12% of TC. The results confirm that wood combustion is a major source to OC and EC in Northern Europe during winter.
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| 466. |
- Glover, C. J., et al.
(författare)
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Stationary and dispersive features in resonant inelastic soft X-ray scattering at the Ge 3p resonances
- 2009
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 173:2-3, s. 103-107
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Tidskriftsartikel (refereegranskat)abstract
- Resonant inelastic soft X-ray scattering at the 3p resonances in crystalline Ge is presented. Both stationary and dispersive features are observed in a wide energy range above as well as below the ionization limits. These observations are in agreement with theoretical predictions based on a two-step model where the initially excited electron has no influence on the emission step. Excess population of states in the conduction band is found, and discussed in terms of attosecond electron dynamics. (c) 2009 Elsevier B.V. All rights reserved.
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| 467. |
- Gobel, K., et al.
(författare)
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Coulomb dissociation of 16O into 4He and 12C
- 2020
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1668:1
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Konferensbidrag (refereegranskat)abstract
- We measured the Coulomb dissociation of 16O into 4He and 12C at the R3B setup in a first campaign within FAIR Phase 0 at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. The goal was to improve the accuracy of the experimental data for the 12C(a,?)16O fusion reaction and to reach lower center-ofmass energies than measured so far. The experiment required beam intensities of 109 16O ions per second at an energy of 500 MeV/nucleon. The rare case of Coulomb breakup into 12C and 4He posed another challenge: The magnetic rigidities of the particles are so close because of the same mass-To-charge-number ratio A/Z = 2 for 16O, 12C and 4He. Hence, radical changes of the R3B setup were necessary. All detectors had slits to allow the passage of the unreacted 16O ions, while 4He and 12C would hit the detectors' active areas depending on the scattering angle and their relative energies. We developed and built detectors based on organic scintillators to track and identify the reaction products with sufficient precision.
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| 468. |
- Gocht, Stephan, et al.
(författare)
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End-to-End Verification for Subgraph Solving
- 2024
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Ingår i: Proceedings of the AAAI Conference on Artificial Intelligence. - 2374-3468 .- 2159-5399. ; 38:8, s. 8038-8047
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Konferensbidrag (refereegranskat)abstract
- Modern subgraph-finding algorithm implementations consist of thousands of lines of highly optimized code, and this complexity raises questions about their trustworthiness. Recently, some state-of-the-art subgraph solvers have been enhanced to output machine-verifiable proofs that their results are correct. While this significantly improves reliability, it is not a fully satisfactory solution, since end-users have to trust both the proof checking algorithms and the translation of the high-level graph problem into a low-level 0-1 integer linear program (ILP) used for the proofs. In this work, we present the first formally verified toolchain capable of full end-to-end verification for subgraph solving, which closes both of these trust gaps. We have built encoder frontends for various graph problems together with a 0-1 ILP (a.k.a. pseudo-Boolean) proof checker, all implemented and formally verified in the CAKEML ecosystem. This toolchain is flexible and extensible, and we use it to build verified proof checkers for both decision and optimization graph problems, namely, subgraph isomorphism, maximum clique, and maximum common (connected) induced subgraph. Our experimental evaluation shows that end-to-end formal verification is now feasible for a wide range of hard graph problems.
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| 469. |
- Goffeng, Magnus C H T, 1987, et al.
(författare)
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Clusters of eigenvalues for the magnetic Laplacian with Robin condition
- 2016
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Ingår i: Journal of Mathematical Physics. - : AIP Publishing. - 0022-2488 .- 1089-7658. ; 57:6
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Tidskriftsartikel (refereegranskat)abstract
- We study the Schrodinger operator with a constant magnetic field in the exterior of a compact domain in Euclidean space. Functions in the domain of the operator are subject to a boundary condition of the third type (a magnetic Robin condition). In addition to the Landau levels, we obtain that the spectrum of this operator consists of clusters of eigenvalues around the Landau levels and that they do accumulate to the Landau levels from below. We give a precise asymptotic formula for the rate of accumulation of eigenvalues in these clusters, which is independent of the boundary condition. Published by AIP Publishing.
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| 470. |
- Goffo, Elisa, et al.
(författare)
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Company for the Ultra-high Density, Ultra-short Period Sub-Earth GJ 367 b: Discovery of Two Additional Low-mass Planets at 11.5 and 34 Days
- 2023
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Ingår i: Astrophysical Journal Letters. - : Institute of Physics (IOP). - 2041-8213 .- 2041-8205. ; 955:1
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Tidskriftsartikel (refereegranskat)abstract
- GJ 367 is a bright (V ≈ 10.2) M1 V star that has been recently found to host a transiting ultra-short period sub-Earth on a 7.7 hr orbit. With the aim of improving the planetary mass and radius and unveiling the inner architecture of the system, we performed an intensive radial velocity follow-up campaign with the HARPS spectrograph—collecting 371 high-precision measurements over a baseline of nearly 3 yr—and combined our Doppler measurements with new TESS observations from sectors 35 and 36. We found that GJ 367 b has a mass of M b = 0.633 ± 0.050 M ⊕ and a radius of R b = 0.699 ± 0.024 R ⊕, corresponding to precisions of 8% and 3.4%, respectively. This implies a planetary bulk density of ρ b = 10.2 ± 1.3 g cm−3, i.e., 85% higher than Earth’s density. We revealed the presence of two additional non-transiting low-mass companions with orbital periods of ∼11.5 and 34 days and minimum masses of M c sin i c = 4.13 ± 0.36 M ⊕ and M d sin i d = 6.03 ± 0.49 M ⊕, respectively, which lie close to the 3:1 mean motion commensurability. GJ 367 b joins the small class of high-density planets, namely the class of super-Mercuries, being the densest ultra-short period small planet known to date. Thanks to our precise mass and radius estimates, we explored the potential internal composition and structure of GJ 367 b, and found that it is expected to have an iron core with a mass fraction of 0.91 − 0.23 + 0.07 . How this iron core is formed and how such a high density is reached is still not clear, and we discuss the possible pathways of formation of such a small ultra-dense planet.
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