| 1. |
- Ahmed, M., et al.
(författare)
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Search for the lepton-family-number nonconserving decay μ +→e +γ
- 2002
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Ingår i: Physical Review D. - : American Physical Society. - 1550-7998 .- 1550-2368. ; 65:11
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Tidskriftsartikel (refereegranskat)abstract
- The MEGA experiment, which searched for the muon- and electron-number violating decay μ +→e + γ, is described. The spectrometer system, the calibrations, the data taking procedures, the data analysis, and the sensitivity of the experiment are discussed. The most stringent upper limit on the branching ratio, B(μ + →e + γ)<1.2×10 -11 with 90% confidence, is derived from a likelihood analysis.
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| 2. |
- Khodorkovskii, M. A., et al.
(författare)
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Electronic spectra of XeNe molecules in the range 77100-90100 cm(-1) near Xe* (6p, 5d, 6p', 7s, 7p, 6d) obtained by the (3+1) REMPI and (2+1) REMPI methods
- 2010
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Ingår i: Optics and Spectroscopy. - 0030-400X .- 1562-6911. ; 108:6, s. 899-914
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Tidskriftsartikel (refereegranskat)abstract
- The electronic spectra of XeNe molecules in the range of 77100-90100 cm(-1) are measured by the method of laser resonance multiphoton ionization in a supersonic jet. The photoionization spectra are obtained upon two- and three-photon excitations of molecules and their ionization by the next photon. In the range of 80300-90100 cm(-1) near Xe*(5d, 6p', 6d, 7s, and 7p), the spectra are obtained for the first time. A whole number of vibrational systems are measured in this range. The majority of vibrational systems near Xe* (5d, 6d, 7p, and 7s) are located in the red range with respect to their dissociation limits. In the blue range with respect to the dissociation limits, continua corresponding to transitions of molecules from the ground state to repulsive potential curves of excited states are detected. For a number of excited states of XeNe molecules, the vibrational analysis is performed and molecular constants are estimated.
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| 3. |
- Khodorkovskii, M. A., et al.
(författare)
-
Multiphoton mass spectra of Xe-2 molecules in the range of excited Xe*(6p, 5d) atoms
- 2006
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Ingår i: Optics and Spectroscopy. ; 100:4, s. 497-509
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Tidskriftsartikel (refereegranskat)abstract
- The (2 + 1) photoionization mass spectra of Xe-2 molecules are studied in a supersonic jet upon excitation by laser radiation in the energy range 80321.3-77821 cm(-1), corresponding to the dissociation of the Xe-2 molecule into atoms Xe(S-1(0)) + Xe*(6p, 5d). Several vibrational progressions are observed, which are attributed to two-photon transitions of Xe-2 from the ground state to the excited states of the 0(g)(+), 1(g), and 2(g) symmetries. Based on the analysis of these progressions, the molecular constants of a number of excited states of Xe? are estimated.
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| 4. |
- Khodorkovskii, M. A., et al.
(författare)
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Multiphoton mass spectra of XeKr molecules in the range of excited Xe*6p[5/2](2,3) atoms
- 2007
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Ingår i: Optics and Spectroscopy. - 0030-400X .- 1562-6911. ; 102:6, s. 834-841
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Tidskriftsartikel (refereegranskat)abstract
- Data on excited states of XeKr molecules in the energy range 78280-77600 cm(-1) are obtained. Using the method of multiphoton laser photoionization of molecules in a supersonic jet, five vibrational progressions of XeKr molecules are obtained, which are attributed to five electronic-vibrational transitions from the ground state of the XeKr molecule of the symmetry 0(+) to excited states of the symmetry Omega = 0(+), 1, 2 with the dissociation limit (KrS0)-S-1 + Xe*6p[5/2](2) and of the symmetry Omega = 1, 2 with the dissociation limit Kr + Xe*6p[5/2](3). The molecular constants of the corresponding excited states of the XeKr molecule are estimated.
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| 5. |
- Khodorkovskii, M. A., et al.
(författare)
-
Study of the lowest electronic states of Xe-2, XeKr, and XeAr molecules by the method of multiphoton resonance ionization
- 2008
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Ingår i: Optics and Spectroscopy. - 0030-400X .- 1562-6911. ; 104:5, s. 674-685
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Tidskriftsartikel (refereegranskat)abstract
- The spectra of Xe-2, XeKr, and XeAr molecules in the range 66 500-68 800 cm(-1) are obtained by the methods of (2 + n) and (3 + n) (n = 1, 2, 3) resonance multiphoton ionization during the registration of molecular and atomic ions. The combining of two-and three-photon resonance excitations of Xe-2 molecules makes it possible to obtain the spectra caused by transitions from the ground state X0(g)(+) to the excited states of Xe*6s[3/2](1,2)degrees(XeS0)-S-1 molecules both of the even (0(g)(+), 1(g) ) and of the odd (B0(u)(+), B'1(u) , 2(u) ) symmetries. The data on the Omega = 2(u) state of the Xe-2 molecule with the dissociation limit Xe*6s[3/2](2)degrees + (XeS0)-S-1 and on the Omega = 1 state of the XeAr molecule with the dissociation limit Xe*6s[3/2](1)degrees (ArS0)-S-1 are obtained for the first time. The potential curve of the excited 2(u) state of the Xe*6s[3/2](2)degrees (XeS0)-S-1 molecule is repulsive and intersects the potential curve of the B0(u) + state of the Xe*6s[3/2](1)degrees (XeS0)-S-1 molecule. In the case of the three-photon excitation, it is observed that all the bands in the spectra of XeKr and XeAr molecules are broadened and are shifted, which indicates that, in an intense light field, the influence of the dynamic Stark effect is significant.
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| 6. |
- Szymanski, J. J., et al.
(författare)
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A study of the decay mu –> e gamma by the MEGA experiment
- 1996
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Ingår i: Proceedings, 9th Meeting, DPF'96, Minneapolis, USA, August 11-15, 1996. Vol. 1, 2.. ; , s. 1450-1452
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Konferensbidrag (refereegranskat)
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| 7. |
- Szymanski, J. J., et al.
(författare)
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MEGA : A search for the decay mu –> e gamma
- 1994
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Ingår i: Intersections between particle and nuclear physics. Proceedings, 5th Conference, St. Petersburg, USA, May 31-June 6, 1994. ; , s. 789-792
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Konferensbidrag (refereegranskat)
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| 8. |
- Maes, S.L., et al.
(författare)
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Environmental drivers of increased ecosystem respiration in a warming tundra
- 2024
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 629:8010, s. 105-113
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Tidskriftsartikel (refereegranskat)abstract
- Arctic and alpine tundra ecosystems are large reservoirs of organic carbon. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain. This hampers the accuracy of global land carbon–climate feedback projections. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9–2.0 °C] in air and 0.4 °C [CI 0.2–0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22–38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.
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| 9. |
- Amann, F., et al.
(författare)
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A search for murarregamma at the level of 10-13
- 1991
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Ingår i: Proceedings of the 25th International Conference on High Energy Physics. - 9810024347 ; , s. 1070-1071
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Konferensbidrag (refereegranskat)abstract
- The MEGA experiment, which is a search for the decay murarregamma with a branching ratio sensitivity of about 10-13, employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5-T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the design have been validated in engineering runs; data taking will begin in 1990 with much of the electron arm and one pair spectrometer layer installed.
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| 10. |
- Fredholm, BB, et al.
(författare)
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Consequences of eliminating adenosine A(1) receptors in mice
- 2003
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Ingår i: Drug Development Research (Proceedings of the Seventh International Symposium on Adenosine and Adenine Nucleotides - Part 1). - : Wiley. - 1098-2299 .- 0272-4391. ; 58, s. 350-
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Konferensbidrag (refereegranskat)abstract
- The second coding exon of the adenosine A, receptor gene was eliminated by homologous recombination. The phenotype of mice (mixed C57B6/129OlaHsd background) was studied, using siblings from matings of heterozygous mice. Among the offspring the ratio between+/+, +/-and -/-animals was 1:2:1. Over the first half-year-at least-growth and viability were the same in all genotypes. Binding of A(1) ligands was eliminated in-/-mice and halved in+/-mice. Blood pressure was increased in-/-mice and this was paralleled by an increase in plasma renin. Heart rate was unaffected, as was contractility. Furthermore, the response of the perfused heart to ischemia was similar in+/+and -/-hearts. However, remote preconditioning was eliminated in-/-mouse hearts. Tubuloglomerular feedback in the kidney was also lost in-/-mice. The analgesic response to a non-selective adenosing receptor agonist was lost in-/-mice, which also showed hyperalgesia in the tail-flick test. There was a slight hypoactivity in-/-mice, but responses to caffeine were essentially normal. The inhibition of excitatory neurotransmission in hippocampus by adenosine was lost in-/-mice and reduced in+/-mice. Responses to ATP were affected similarly. Hypoxic depression of synaptic transmission was essentially eliminated in hippocampus and hypoxic decrease in spinal respiratory neuron firing was markedly reduced. These results show that adenosine A, receptors play a physiologically important role in the kidney, spinal cord, and hippocampus and that they are critically important in the adaptive responses to hypoxia. (C) 2003 Wiley-Liss, Inc.
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