| 1. |
- Aad, G., et al.
(författare)
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- 2012
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swepub:Mat__t (refereegranskat)
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| 2. |
- Aad, G., et al.
(författare)
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- 2012
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swepub:Mat__t (refereegranskat)
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| 3. |
- Rodriguez, D., et al.
(författare)
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MATS and LaSpec : High-precision experiments using ion traps and lasers at FAIR
- 2010
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Ingår i: The European physical journal. Special topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 183, s. 1-123
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Forskningsöversikt (refereegranskat)abstract
- Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique ""fingerprint"". Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10(-5) to below 10(-8) for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10(-9) can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e. g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with beta-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
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| 4. |
- Khuyagbaatar, J., et al.
(författare)
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48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr
- 2014
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Ingår i: Physical Review Letters. - 1079-7114. ; 112:17
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Tidskriftsartikel (refereegranskat)abstract
- The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294-117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-lived (T1/2=1.0+1.9−0.4 h) α-emitter 270Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an “island of stability.”
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| 5. |
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| 6. |
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| 7. |
- Chalmers, J. R., et al.
(författare)
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Report from the third international consensus meeting to harmonise core outcome measures for atopic eczema/dermatitis clinical trials (HOME)
- 2014
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 1365-2133 .- 0007-0963. ; 171:6, s. 1318-1325
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Tidskriftsartikel (refereegranskat)abstract
- This report provides a summary of the third meeting of the Harmonising Outcome Measures for Eczema (HOME) initiative held in San Diego, CA, U.S.A., 6-7 April 2013 (HOME III). The meeting addressed the four domains that had previously been agreed should be measured in every eczema clinical trial: clinical signs, patient-reported symptoms, long-term control and quality of life. Formal presentations and nominal group techniques were used at this working meeting, attended by 56 voting participants (31 of whom were dermatologists). Significant progress was made on the domain of clinical signs. Without reference to any named scales, it was agreed that the intensity and extent of erythema, excoriation, oedema/papulation and lichenification should be included in the core outcome measure for the scale to have content validity. The group then discussed a systematic review of all scales measuring the clinical signs of eczema and their measurement properties, followed by a consensus vote on which scale to recommend for inclusion in the core outcome set. Research into the remaining three domains was presented, followed by discussions. The symptoms group and quality of life groups need to systematically identify all available tools and rate the quality of the tools. A definition of long-term control is needed before progress can be made towards recommending a core outcome measure.
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| 8. |
- Düllmann, Ch. E., et al.
(författare)
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Production and Decay of Element 114: High Cross Sections and the New Nucleus 277Hs
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 104:25
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reaction 244Pu(48Ca, 3-4n)288,289114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of 288,289114. At a compound nucleus excitation energy of E* = 39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8(-3.1)(+3.9) pb. At E* = 36.1-39.5 MeV, that of the 3n evaporation channel was 8.0-(+7.4)(4.5) pb. In one of the 3n evaporation channel decay chains, a previously unobserved alpha branch in 281Ds was observed ( probability to be of random origin from background: 0.1%). This alpha decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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| 9. |
- Forsberg, Ulrika, et al.
(författare)
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First Experiment at TASCA Towards X-Ray Fingerprinting of Element 115 Decay Chains
- 2012
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 43:2, s. 305-311
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Tidskriftsartikel (refereegranskat)abstract
- To identify the atomic number of superheavy nuclei produced in Ca-48-induced fusion-evaporation reactions, an experiment aiming at measuring characteristic X-rays is being prepared at GSI, Darmstadt, Germany. The gas-filled separator TASCA will be employed, sending the residues towards the multi-coincidence detector setup TASISpec. Two ion-optical modes relying on differing magnetic polarities of the quadrupole magnets can be used at TASCA. New simulations and experimental tests of transmission and background suppression for these two focusing modes into TASISpec are presented.
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| 10. |
- Gates, J. M., et al.
(författare)
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First Superheavy Element Experiments at the GSI Recoil Separator TASCA: The Production and Decay of Element 114 in the 244Pu(48Ca,3-4n) Reaction
- 2011
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 83:5
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Tidskriftsartikel (refereegranskat)abstract
- Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new a-decay branch in (281)Ds was observed, leading to the new nucleus (277)Hs.
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| 11. |
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| 12. |
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| 13. |
- Forsberg, Ulrika, et al.
(författare)
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Spectroscopic Tools Applied to Element Z = 115 Decay Chains
- 2014
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X .- 2101-6275. - 9782759811755 - 9782759811762 ; 66, s. 02036-02036
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Konferensbidrag (refereegranskat)abstract
- Nuclides that are considered to be isotopes of element Z = 115 were produced in the reaction 48Ca + 243Am at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt. The detector setup TASISpec was used. It was mounted behind the gas-filled separator TASCA. Thirty correlated α-decay chains were found, and the energies of the particles were determined with high precision. Two important spectroscopic aspects of the offline data analysis are discussed in detail: the handling of digitized preamplified signals from the silicon strip detectors, and the energy reconstruction of particles escaping to upstream detectors relying on pixel-by-pixel dead-layer thicknesses.
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| 14. |
- Yakushev, A., et al.
(författare)
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Superheavy Element Flerovium (Element 114) Is a Volatile Metal
- 2014
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 53:3, s. 1624-1629
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of superheavy elements (Z ≥ 104) and their chemical properties are dominated by relativistic effects. Recently two superheavy elements were recognized by the IUPAC and named flerovium (Fl, Z = 114) and livermorium (Lv, Z = 116). Fl is the heaviest element with which chemical experiments were performed. Here, we report on experiments that help answering the long-standing question whether Fl behaves rather like a noble gas or like a metal.
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| 15. |
- Droese, C., et al.
(författare)
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High-precision Mass Measurements of 203-207Rn and 213Ra with SHIPTRAP
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 49:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- The masses of the nuclides Rn203-207 and Ra-213 were measured directly for the first time with the Penning-trap mass spectrometer SHIPTRAP at GSI Darmstadt. The results confirm the previously determined mass values. The mass uncertainties for Rn-205 and Ra-213 were significantly reduced. The results are relevant for the investigation of the nuclear shell structure between N = 82 and N = 126. As an indicator of structural changes the two-neutron separation energies S-2n(Z, N) have been studied.
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| 16. |
- Rudolph, Dirk, et al.
(författare)
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Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains
- 2014
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 45, s. 263-272
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Tidskriftsartikel (refereegranskat)abstract
- Produced in the reaction 48Ca+243Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum für Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.
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| 17. |
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| 18. |
- Rudolph, Dirk, et al.
(författare)
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Spectroscopy of Element 115 Decay Chains
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 111:11
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution , X-ray and gamma-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated alpha-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.
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| 19. |
- Lundkvist, GBS, et al.
(författare)
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Clock gene expression during chronic inflammation induced by infection with Trypanosoma brucei brucei in rats
- 2010
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Ingår i: Journal of biological rhythms. - : SAGE Publications. - 1552-4531 .- 0748-7304. ; 25:2, s. 92-102
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Tidskriftsartikel (refereegranskat)abstract
- African sleeping sickness is characterized by alterations in rhythmic functions. It is not known if the disease affects the expression of clock genes, which are the molecular basis for rhythm generation. We used a chronic rat model of experimental sleeping sickness, caused by the extracellular parasite Trypanosoma brucei brucei (Tb brucei), to study the effects on clock gene expression. In tissue explants of pituitary glands from Period1- luciferase ( Per1-luc) transgenic rats infected with Tb brucei, the period of Per1-luc expression was significantly shorter. In explants containing the suprachiasmatic nuclei (SCN), the Per1-luc rhythms were flat in 21% of the tissues. We also examined the relative expression of Per1, Clock, and Bmal1 mRNA in the SCN, pineal gland, and spleen from control and infected rats using qPCR. Both Clock and Bmal1 mRNA expression was reduced in the pineal gland and spleen following Tb brucei infection. Infected rats were periodic both in core body temperature and in locomotor activity; however, early after infection, we observed a significant decline in the amplitude of the locomotor activity rhythm. In addition, both activity and body temperature rhythms exhibited decreased regularity and “robustness.” In conclusion, although experimental trypanosome infection has previously been shown to cause functional disturbances in SCN neurons, only 21% of the SCN explants had disturbed Per1-luc rhythms. However, our data show that the infection overall alters molecular clock function in peripheral clocks including the pituitary gland, pineal gland, and spleen.
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| 20. |
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| 21. |
- Block, Stephan, 1978, et al.
(författare)
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Characterization of bonds formed between platelet factor 4 and negatively charged drugs using single molecule force spectroscopy
- 2014
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 10:16, s. 2775-2784
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Tidskriftsartikel (refereegranskat)abstract
- Immunogenicity (i.e., the ability to initiate immune reactions) is one of the major challenges for the development of new drugs, as it may turn the developed drug therapeutically ineffective or cause severe immune-related effects. Using single molecule force spectroscopy, we study rupture forces between the positively charged, endogenous protein platelet factor 4 (PF4; also known as CXC chemokine ligand 4, CXCL4) and the antithrombotic drug heparin and other negatively charged glycosaminoglycans (GAGs), which are known to form immunogenic PF4/GAG-complexes (e. g., heparin and dextran sulfate) as well as non-immunogenic complexes (e. g., chondroitin sulfate A). Our measurements suggest that the average number of sulfate groups per monosaccharide unit (i.e., the degree of sulfation DS) does not affect the unbinding characteristics of single PF4/GAG-bonds (reaction coordinate x(0) = 2.2 +/- 0.2 angstrom, energy barrier Delta G approximate to -1 k(B)T). However, the average number of GAG bonds formed to a single PF4 molecule increases with increasing DS as indicated by a rising frequency of unbinding events, suggesting a multivalent binding scheme between PF4 and GAGs. Our studies show that at least three GAG bonds have to be formed to each PF4 molecule to induce epitope formation on the PF4/GAG-complex to which PF4/GAG-complex specific antibodies bind. Hence, GAG-based drugs that form less than three bonds per PF4 molecule are unlikely to constitute PF4/drug-complexes that are of immunologic relevance.
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| 22. |
- Bokalders, Varis, et al.
(författare)
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The whole building handbook : How to design healthy, efficient and sustainable buildings
- 2010
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- The Whole Building Handbook is a compendium of all the issues and strategies that architects need to understand to design and construct sustainable buildings for a sustainable society. The authors move beyond the current definition of sustainability in architecture, which tends to focus on energy-efficiency, to include guidance for architecture that promotes social cohesion, personal health, renewable energy sources, water and waste recycling systems, permaculture, energy conservation - and crucially, buildings in relation to their place. The authors offer a holistic approach to sustainable architecture and authoritative technical advice, on: * How to design and construct healthy buildings, through choosing suitable materials, healthy service systems, and designing a healthy and comfortable indoor climate, including solutions for avoiding problems with moisture, radon and noise as well as how to facilitate cleaning and maintenance. * How to design and construct buildings that use resources efficiently, where heating and cooling needs and electricity use is minimized and water-saving technologies and garbage recycling technologies are used. * How to 'close' organic waste, sewage, heat and energy cycles. For example, how to design a sewage system that recycles nutrients. * Includes a section on adaptation of buildings to local conditions, looking at how a site must be studied with respect to nature, climate and community structure as well as human activities. The result is a comprehensive, thoroughly illustrated and carefully structured textbook and reference.
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| 23. |
- Nilsson-Örtman, Viktor, 1984-, et al.
(författare)
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Latitudinally structured variation in the temperature dependence of damselfly growth rates
- 2013
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 16:1, s. 64-71
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Tidskriftsartikel (refereegranskat)abstract
- The Metabolic Theory of Ecology predicts that the slope of the rate-temperature relationship, E, remains consistent across traits and organisms, acting as a major determinant of large-scale ecological patterns. Although E has recently been shown to vary systematically, we have a poor understanding of its ecological significance. To address this question, we conducted a common-garden experiment involving six damselfly species differing in distribution, estimating E at the level of full-sib families. Each species was sampled throughout its latitudinal range, allowing us to characterise variation in E along a latitudinal gradient spanning 3600 km. We show that E differs among populations and increases with latitude. E was right-skewness across species, but this was largely an artefact of the latitudinal trend. Increased seasonality towards higher latitude may contribute to the latitudinal trend in E. We conclude that E should be seen as a trait involved in local adaptation.
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