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| 2. |
- Butler, P. A., et al.
(author)
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Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive ^{222}Ra and ^{228}Ra Beams
- 2020
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In: Physical Review Letters. - 1079-7114. ; 124:4
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Journal article (peer-reviewed)abstract
- There is sparse direct experimental evidence that atomic nuclei can exhibit stable "pear" shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in ^{222,228}Ra nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing ^{222}Ra as pear shaped with stable octupole deformation, while ^{228}Ra behaves like an octupole vibrator.
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| 3. |
- Butler, P. A., et al.
(author)
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The observation of vibrating pear-shapes in radon nuclei
- 2019
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Journal article (peer-reviewed)abstract
- There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.
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| 4. |
- Spagnoletti, P., et al.
(author)
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Coulomb excitation of Rn 222
- 2022
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In: Physical Review C. - 2469-9985. ; 105:2
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Journal article (peer-reviewed)abstract
- The nature of quadrupole and octupole collectivity in Rn222 was investigated by determining the electric-quadrupole (E2) and octupole (E3) matrix elements using subbarrier, multistep Coulomb excitation. The radioactive Rn222 beam, accelerated to 4.23 MeV/u, was provided by the HIE-ISOLDE facility at CERN. Data were collected in the Miniball γ-ray spectrometer following the bombardment of two targets, Sn120 and Ni60. Transition E2 matrix elements within the ground-state and octupole bands were measured up to 10ℏ and the results were consistent with a constant intrinsic electric-quadrupole moment, 518(11)efm2. The values of the intrinsic electric-octupole moment for the 0+→3- and 2+→5- transitions were found to be respectively 2360-210+300efm3 and 2300-500+300efm3 while a smaller value, 1200-900+500efm3, was found for the 2+→1- transition. In addition, four excited non-yrast states were identified in this work via γ-γ coincidences.
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| 5. |
- Hilton, J., et al.
(author)
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α -spectroscopy studies of the new nuclides Pt 165 and Hg 170
- 2019
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In: Physical Review C. - 2469-9985. ; 100:1
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Journal article (peer-reviewed)abstract
- The new nuclides Pt165 and Hg170 were produced in the reactions Mo92(Kr78,5n) and Ru96(Kr78,4n) at bombarding energies of 418 MeV and 390 MeV, respectively. For Hg170 an α-particle energy of Eα=7590(30)keV and half-life of t1/2=0.08-0.04+0.40ms were deduced, while for Pt165 the corresponding values were 7272(14) keV and 0.26-0.09+0.26ms. Comparison of the reduced α-decay widths with systematics indicates that both α decays are unhindered. Although combining the measured α-decay Q values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their α-decay half-lives are too short for this decay mode to compete. Improved data were also obtained for Pt166,167, produced via the Ru96(Kr78,α4n) and Ru96(Kr78,α3n) reactions at bombarding energies of 390 MeV and 418 MeV.
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| 6. |
- Pereira-López, X., et al.
(author)
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In-beam γ -ray spectroscopy of 94 Ag
- 2023
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 59:3
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Journal article (peer-reviewed)abstract
- A recoil-beta-tagging experiment has been performed to study the excited T= 0 and T= 1 states in the odd–odd N= Z nucleus 94Ag, populated via the 40Ca(58Ni,1p3n)94Ag reaction. The experiment was conducted using the MARA recoil separator and JUROGAM3 array at the Accelerator Laboratory of the University of Jyväskylä. Through correlating fast, high-energy beta decays at the MARA focal plane with prompt γ rays emitted at the reaction target, a number of transitions between excited states in 94Ag have been identified. The timing characteristics of these transitions confirm that they fall within decay sequences that feed the short-lived T= 1 ground state of 94Ag. The transitions are proposed to proceed within and between the sets of states with T= 0 and T= 1. Possible correspondence between some of these transitions from analog states in 94Pd has been discussed, and shell-model calculations including multipole and monopole electromagnetic effects have been presented, in order to enable predictions of the decay patterns between the T= 0 and T= 1 states and to allow a theoretical set of Coulomb energy differences to be calculated for the A= 94 T= 1 analog states.
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| 7. |
- Stryjczyk, M., et al.
(author)
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Decay studies of the long-lived states in Tl 186
- 2020
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In: Physical Review C. - 2469-9985. ; 102:2
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Journal article (peer-reviewed)abstract
- Decay spectroscopy of the long-lived states in Tl186 has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The α decay from the low-spin (2-) state in Tl186 was observed for the first time and a half-life of 3.4-0.4+0.5 s was determined. Based on the α-decay energy, the relative positions of the long-lived states were fixed, with the (2-) state as the ground state, the 7(+) state at 77(56) keV, and the 10(-) state at 451(56) keV. The level scheme of the internal decay of the Tl186(10(-)) state [T1/2=3.40(9) s], which was known to decay solely through emission of 374-keV γ-ray transition, was extended and a lower limit for the β-decay branching bβ>5.9(3)% was determined. The extracted retardation factors for the γ decay of the 10(-) state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the πd3/2 shell in the isomeric decay and significant structure differences between Tl184 and Tl186.
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| 12. |
- Rosiak, D., et al.
(author)
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Enhanced Quadrupole and Octupole Strength in Doubly Magic Sn 132
- 2018
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In: Physical Review Letters. - 0031-9007. ; 121:25
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Journal article (peer-reviewed)abstract
- The first 2+ and 3- states of the doubly magic nucleus Sn132 are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The Sn132 ions are accelerated to an energy of 5.49 MeV/nucleon and impinged on a Pb206 target. Deexciting γ rays from the low-lying excited states of the target and the projectile are recorded in coincidence with scattered particles. The reduced transition strengths are determined for the transitions 0g.s.+→21+, 0g.s.+→31-, and 21+→31- in Sn132. The results on these states provide crucial information on cross-shell configurations which are determined within large-scale shell-model and Monte Carlo shell-model calculations as well as from random-phase approximation and relativistic random-phase approximation. The locally enhanced B(E2;0g.s.+→21+) strength is consistent with the microscopic description of the structure of the respective states within all theoretical approaches. The presented results of experiment and theory can be considered to be the first direct verification of the sphericity and double magicity of Sn132.
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| 17. |
- Henrich, C., et al.
(author)
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Coulomb excitation of 142Xe
- 2018
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In: Acta Physica Polonica B. - 0587-4254. ; 49:3, s. 529-533
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Journal article (peer-reviewed)abstract
- The even-even nucleus 142Xe lies north-east of the doubly magic 132Sn on the neutron-rich side of the nuclear chart. In order to gain further information on the octupole collectivity and the evolution of quadrupole collectivity in this region, a "safe" Coulomb excitation experiment was carried out at the new HIE-ISOLDE facility (CERN) at the end of 2016. As the gamma-ray detector the Miniball spectrometer was used. Beam and target nuclei were detected using C-REX, i.e. an array of segmented Si detectors, covering forward as well as backward angles in the laboratory frame.
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| 23. |
- Lennernäs, Hans, et al.
(author)
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Oral biopharmaceutics tools - Time for a new initiative - An introduction to the IMI project OrBiTo
- 2014
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In: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 57:SI, s. 292-299
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Research review (peer-reviewed)abstract
- OrBiTo is a new European project within the IMI programme in the area of oral biopharmaceutics tools that includes world leading scientists from nine European universities, one regulatory agency, one non-profit research organization, four SMEs together with scientists from twelve pharmaceutical companies. The OrBiTo project will address key gaps in our knowledge of gastrointestinal (GI) drug absorption and deliver a framework for rational application of predictive biopharmaceutics tools for oral drug delivery. This will be achieved through novel prospective investigations to define new methodologies as well as refinement of existing tools. Extensive validation of novel and existing biopharmaceutics tools will be performed using active pharmaceutical ingredient (API), formulations and supporting datasets from industry partners. A combination of high quality in vitro or in silico characterizations of API and formulations will be integrated into physiologically based in silica biopharmaceutics models capturing the full complexity of GI drug absorption. This approach gives an unparalleled opportunity to initiate a transformational change in industrial research and development to achieve model-based pharmaceutical product development in accordance with the Quality by Design concept. Benefits include an accelerated and more efficient drug candidate selection, formulation development process, particularly for challenging projects such as low solubility molecules (BCS II and IV), enhanced and modified-release formulations, as well as allowing optimization of clinical product performance for patient benefit. In addition, the tools emerging from OrBiTo are expected to significantly reduce demand for animal experiments in the future as well as reducing the number of human bioequivalence studies required to bridge formulations after manufacturing or composition changes.
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| 33. |
- Guseva, S., et al.
(author)
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Variable Physical Drivers of Near-Surface Turbulence in a Regulated River
- 2021
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In: Water resources research. - : American Geophysical Union (AGU). - 0043-1397 .- 1944-7973. ; 57:11
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Journal article (peer-reviewed)abstract
- Inland waters, such as lakes, reservoirs and rivers, are important sources of climate forcing trace gases. A key parameter that regulates the gas exchange between water and the atmosphere is the gas transfer velocity, which itself is controlled by near-surface turbulence in the water. While in lakes and reservoirs, near-surface turbulence is mainly driven by atmospheric forcing, in shallow rivers and streams it is generated by bottom friction of gravity-forced flow. Large rivers represent a transition between these two cases. Near-surface turbulence has rarely been measured in rivers and the drivers of turbulence have not been quantified. We analyzed continuous measurements of flow velocity and quantified turbulence as the rate of dissipation of turbulent kinetic energy over the ice-free season in a large regulated river in Northern Finland. Measured dissipation rates agreed with predictions from bulk parameters, including mean flow velocity, wind speed, surface heat flux, and with a one-dimensional numerical turbulence model. Values ranged from to . Atmospheric forcing or gravity was the dominant driver of near-surface turbulence for similar fraction of the time. Large variability in near-surface dissipation rate occurred at diel time scales, when the flow velocity was strongly affected by downstream dam operation. By combining scaling relations for boundary-layer turbulence at the river bed and at the air-water interface, we derived a simple model for estimating the relative contributions of wind speed and bottom friction of river flow as a function of depth.Plain Language SummaryInland water bodies such as lakes, reservoirs and rivers are an important source of climate forcing trace gases to the atmosphere. Gas exchange between water and the atmosphere is regulated by the gas transfer velocity and the concentration difference between the water surface and the atmosphere. The gas transfer velocity depends on near-surface turbulence, but robust formulations have not been developed for river systems. Their surface area is sufficiently large for meteorological forcing to cause turbulence, as in lakes and reservoirs, but turbulence generated from bed and internal friction of gravity-driven flows is also expected to contribute. Here we quantify near-surface turbulence using data from continuous air and water side measurements conducted over the ice-free season in a large subarctic regulated river in Finland. We find that turbulence, quantified as the dissipation rate of turbulent kinetic energy, is well described using equations for predicting turbulence from meteorological data for sufficiently high wind speeds whereas the contribution from bottom shear dominated at higher flow velocities. A one-dimensional river model successfully captured these processes. We provide a fundamental model for estimating the relative contributions of atmospheric forcing and bottom friction as a function of depth.
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| 34. |
- Helenius, K., et al.
(author)
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Overlap between EEC and AEC syndrome and immunodeficiency in a preterm infant with a TP63 variant
- 2023
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In: European Journal of Medical Genetics. - : Elsevier BV. - 1769-7212. ; 66:5
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Journal article (peer-reviewed)abstract
- Pathogenic variants in the transcription factor TP63 gene cause a variety of clinical phenotypes, such as ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome and ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome. Historically, TP63-related phenotypes have been divided into several syndromes based on both the clinical presentation and location of the pathogenic variant on the TP63 gene. This division is complicated by significant overlap between syndromes.Here we describe a patient with clinical characteristics of different TP63-associated syndromes (cleft lip and palate, split feet, ectropion, erosions of the skin and corneas), associated with a de novo heterozygous pathogenic variant c.1681 T>C, p.(Cys561Arg) in exon 13 of the TP63 gene. Our patient also developed enlargement of the left-sided cardiac compartments and secondary mitral insufficiency, which is a novel finding, and immune deficiency, which has only rarely been reported. The clinical course was further complicated by prematurity and very low birth weight. We illustrate the overlapping features of EEC and AEC syndrome and multidisciplinary care needed to address the various clinical challenges.
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| 35. |
- Helmens, Karin F., et al.
(author)
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Warm summers and rich biotic communities during N-Hemisphere deglaciation
- 2018
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In: Global and Planetary Change. - : Elsevier BV. - 0921-8181 .- 1872-6364. ; 167, s. 61-73
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Journal article (peer-reviewed)abstract
- Detailed studies on fossil remains of plants or animals in glacial lake sediments are rare. As a result, environmental conditions right at the moment of deglaciation of the large N-Hemisphere ice-sheets remain largely unknown. Here we study three deglacial phases of the Fennoscandian Ice Sheet as a unique, repeated element in a long sediment record preserved at Soldl in northern Finland. We summarize extensive multi-proxy data (diatoms, phytoliths, chironomids, pollen, spores, non-pollen palynomorphs, macrofossils, lithology, loss-on-ignition, C/N) obtained on glacial lake sediments dated to the early Holocene (ca. 10 kyr BP), early MIS 3 (ca. 50 kyr BP) and early MIS 5a (ca. 80 kyr BP). In contrast to the common view of an unproductive ice-marginal environment, our study reconstructs rich ecosystems both in the glacial lake and along the shores with forest on recently deglaciated land. Higher than present-day summer temperatures are reconstructed based on a large variety of aquatic taxa. Rich biota developed due to the insolation-induced postglacial warming and high nutrient levels, the latter resulting from erosion of fresh bedrock and sediment, leaching of surface soils, decay of plant material under shallow water conditions, and sudden decreases in lake volume. Aquatic communities responded quickly to deglaciation and warm summers and reflect boreal conditions, in contrast to the terrestrial ecosystem which responded with some delay probably due to time required for slow soil formation processes. Birch forest is reconstructed upon deglaciation of the large LGM ice-sheet and shrub tundra following the probably faster melting smaller MIS 4 and MIS 5b ice-sheets. Our study shows that glacial lake sediments can provide valuable palaeo-environmental data, that aquatic biota and terrestrial vegetation rapidly accommodated to new environmental conditions during deglaciation, and that glacial lake ecosystems, and the carbon stored in their sediments, should be included in earth system modeling.
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| 36. |
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| 37. |
- Kjebon, Olle, et al.
(author)
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1.55 μm buried heterostructure laser via regrowth of semi-insulating InP:Fe around vertical mesas fabricated by reactive ion etching using methane and hydrogen
- 1991
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 59:3, s. 235-255
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Journal article (peer-reviewed)abstract
- A GaInAsP/InP Fabry-Perot-type buried-heterostructure quantum well laser operating at 1.55 μm has been realized utilizing iron-doped semi-insulating InP around vertical mesas fabricated by reactive ion etching using methane and hydrogen. A maximum cw output power of 19 mW has been achieved on as-cleaved chips of 300 μm length with a quantum efficiency of 21% per facet. Threshold currents lie between 20 and 25 mA. As low as 2 Ω series resistance has been measured despite an ohmic contact area not exceeding that of the 2-μm-wide mesa. A 3 dB bandwidth of 7.5 GHz at 12 mW output power is obtained from the small-signal frequency modulation measurements.
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| 41. |
- Nordell, Nils, et al.
(author)
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Diffusion of Zn and Mg in AlGaAs/GaAs structures grown by metalorganic vapor-phase epitaxy
- 1990
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 67:2, s. 778-786
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Journal article (peer-reviewed)abstract
- The diffusion of thin, highly p-doped layers in AlGaAs/GaAs single- and double-heterostructures, grown by metalorganic vapor-phase epitaxy, was studied with C-V etch profiling and secondary ion mass spectroscopy. The effect of different post-growth heat treatments was investigated and diffusion coefficients for both magnesium and zinc were measured. It was found that Mg diffuses about twice as fast Zn and that the order of magnitude of the diffusion coefficient is 10-14 cm2 s-1 at 900 °C, the exact value being process and concentration dependent. A model based on the interstitial-substitutional diffusion mechanism with suitable kinetic limitations was successfully used to simulate the observed dopant concentration profiles.We also found an anomalous strong diffusion of zinc from GaAs into highly n-doped AlGaAs. Detailed results on this and other structures are presented and implications for optimal design of heterostructure devices such as bipolar transistors are discussed.
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| 42. |
- Ojala, A. E. K., et al.
(author)
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Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet
- 2019
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In: Annals of Glaciology. - : Cambridge University Press (CUP). - 0260-3055 .- 1727-5644. ; 60:80, s. 115-126
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Journal article (peer-reviewed)abstract
- High-resolution digital elevation models of Finland and Sweden based on LiDAR (Light Detection and Ranging) reveal subglacial landforms in great detail. We describe the ice-sheet scale distribution and morphometric characteristics of a glacial landform that is distinctive in morphology and occurs commonly in the central parts of the former Scandinavian Ice Sheet, especially up-ice of the Younger Dryas end moraine zone. We refer to these triangular or V-shaped landforms as murtoos (singular, `murtoo'). Murtoos are typically 30-200 m in length and 30-200 m in width with a relief of commonly <5 m. Murtoos have straight and steep edges, a triangular tip oriented parallel to ice-flow direction, and an asymmetric longitudinal profile with a shorter, but steeper down-ice slope. The spatial distribution of murtoos and their geomorphic relation to other landforms indicate that they formed subglacially during times of climate warming and rapid retreat of the Scandinavian Ice Sheet when large amounts of meltwater were delivered to the bed. Murtoos are formed under warm-based ice and may be associated with a non-channelized subglacial hydraulic system that evacuated large discharges of subglacial water.
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| 43. |
- Ojala, O., et al.
(author)
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Associations of impulsivity, hyperactivity, and inattention with nonsuicidal self-injury and suicidal behavior: longitudinal cohort study following children at risk for neurodevelopmental disorders into mid-adolescence
- 2022
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In: BMC Psychiatry. - : Springer Science and Business Media LLC. - 1471-244X. ; 22:1
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Journal article (peer-reviewed)abstract
- Background The knowledge of how the separate Attention-Deficit/Hyperactivity Disorder (ADHD) subdimensions (impulsivity, hyperactivity, and inattention) are associated with nonsuicidal self-injury (NSSI) and suicidal behavior (SB) is limited. The objective of this study was to investigate the associations of childhood ADHD subdimensions with NSSI and SB in children at risk of neurodevelopmental disorders (NDDs; including ADHD). Methods The sample (N = 391) included twin pairs where at least one twin screened positive for at least one NDD or common comorbidity at age 9 or 12. Data on ADHD subdimensions was collected through a telephone interview with a caregiver/legal guardian at age 9 or 12, and data on NSSI and SB was collected through an in-person clinical assessment at age 15. The associations between the ADHD subdimensions and NSSI or SB were tested in three different models: (1) univariable, (2) together with the other ADHD subdimensions, and (3) in a confounder-adjusted model including other NDD symptoms in addition to ADHD subdimensions, for NSSI and SB separately. Results A total of 32 (8.2%) adolescents reported life-time engagement of NSSI, and 18 (4.6%) SB. Childhood impulsivity was associated with SB and childhood inattention with NSSI, in all models. Hyperactivity was not meaningfully associated with any of the outcomes. Conclusion Impulsivity and inattention, but not hyperactivity, may be of particular importance in understanding SB and NSSI. Brief screening for impulsivity and inattention in childhood could facilitate detection of children vulnerable to NSSI and SB and indicate valuable information for preventive and intervention strategies.
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| 49. |
- Szczesniak, T., et al.
(author)
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A Time Resolution Study of a Continuous Crystal Detector for TOF PET
- 2010
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In: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 57:1, s. 40-47
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Journal article (peer-reviewed)abstract
- The majority of current Positron Emission Tomography (PET) systems are based on block-detectors consisting of many scintillating pixels read by a smaller number of photomultipliers (PMTs). An improvement of the time resolution, using a common light readout from a cluster of PMTs, was proposed by Kuhn et al., and tested by us earlier with LSO crystals. This, triggered an idea to design a new PET detector optimized for Time of Flight (TOF) systems, based on continuous crystals. In the present work, we report on optimization of timing with a 20 x 20 x 20 mm(3) LYSO crystal coupled to a 16-channel photomultiplier H8711-200MOD from Hamamatsu. First, measurements were performed of the transit time jitter, the number of photoelectrons and the time resolution using a small 10 x 10 x 5 mm(3) LSO crystal coupled to a H8711-200MOD PMT. Results were compared with data collected from fast timing photomultipliers like Photonis XP1020, XP3060, XP20D0 or Hamamatsu R9800. In the second part of the study, the time resolution measurements and the optimization of the system were made with a continuous LYSO crystal. The final results are discussed in terms of the measured photoelectron number and the requirements for the TOF-PET scanners.
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