| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
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| 5. |
- Liu, R. S., et al.
(författare)
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CoFe alloy as middle layer for strong spin dependent quantum well resonant tunneling in MgO double barrier magnetic tunnel junctions
- 2013
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 87:2, s. 024411-
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Tidskriftsartikel (refereegranskat)abstract
- We report on spin dependent quantum well (QW) resonances in the CoFe alloy middle layer of CoFe/MgO/CoFe/MgO/CoFeB double barrier magnetic tunnel junctions. The dI/dV spectra reveal clear resonant peaks for the parallel magnetization configurations, which can be related to the existence of QW resonances obtained from first-principles calculations. We observe that the differential tunneling magnetoresistance (TMR) exhibits an oscillatory behavior as a function of voltage with a sign change as well as a pronounced TMR enhancement at resonant voltages at room temperature. The observation of strong QW resonances indicates that the CoFe film possesses a long majority spin mean-free path, and the substitutional disorder does not cause a significant increase of scattering. Both points are confirmed by first-principles electronic structure calculation. DOI: 10.1103/PhysRevB.87.024411
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| 6. |
- Liu, X, et al.
(författare)
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Synapse density related to cerebral blood flow and symptomatology in frontal lobe degeneration and Alzheimer's disease
- 1999
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 10:Suppl 1, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- In order to evaluate the functional significance of synaptic pathology, synaptic density was quantitated and related to clinical symptomatology and regional cerebral blood flow (rCBF) in 8 patients with frontal lobe degeneration of non-Alzheimer type (FLD) and 19 patients with Alzheimer's disease (AD). Synaptic density was measured in all layers of prefrontal and parietal cortex. The clinical picture of FLD was dominated by a frontal lobe syndrome with changes in personality and behavior, while AD was dominated by temporoparietal symptoms. This parallels the finding of frontal rCBF reductions in FLD patients and temporoparietal reductions in AD patients. Synaptic density was significantly decreased in both FLD and AD, with a regional severity which closely correlated with that of the degeneration, symptomatology and rCBF deficit. The results suggest that synaptic pathology is a likely cause of clinical symptoms and regional metabolic decrement in dementia.
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| 7. |
- Mayer, Manuel, et al.
(författare)
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Constraints on particle acceleration in SS433/W50 from MAGIC and HESS observations
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 612
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Tidskriftsartikel (refereegranskat)abstract
- Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system. Aims. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses (P-orb similar to 13.1 days) and precession of the circumstellar disk (P-pre similar to 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations. Methods. We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to similar to 40-80 h, depending on the region, was employed. Results. No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be less than or similar to 10(-12)-10(-13) TeV-1 cm(-2) s(-1) in an energy interval ranging from similar to few x 100 GeV to similar to few TeV. Integral flux limits down to similar to 10(-12)-10(-13) ph cm(-2) s(-1) and similar to 10(-13)-10(-14) ph cm(-2) s(-1) are obtained at 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jet regions and on the physics of the jet/medium interactions. Conclusions. Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, q(p) <= 2.5 x 10(-5), to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields greater than or similar to 10 mu G is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with E-e up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.
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| 8. |
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| 9. |
- Rahman, M. S., et al.
(författare)
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Exercise Reduces Salivary Morning Cortisol Levels in Patients with Depression
- 2019
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Ingår i: Molecular Neuropsychiatry. - : S. Karger. - 2296-9209 .- 2296-9179. ; 4:4, s. 196-203
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Tidskriftsartikel (refereegranskat)abstract
- Purpose of the Study: Cortisol hypersecretion plays a role in depression pathophysiology. Internet-based cognitive behavioural therapy (ICBT) and physical exercise (PE) are new treatment alternatives for depression, and their long-lasting effect on cortisol is unknown. We investigated cortisol level changes after 12 weeks of ICBT, PE or treatment as usual (TAU).Procedures: The present pre-post repeated measure study analysed data derived from a randomised controlled trial evaluating the effects of 12 weeks’ interventions of ICBT, PE and TAU in depressed primary care patients (Sweden 2011–2013) and aimed at prospectively evaluating the within-group effects of ICBT, PE and TAU on diurnal salivary cortisol levels in a small representative subsample (n = 56, 38 and 27, respectively).Results: We found a marked flattening of the diurnal cortisol slope (p = 0.004) and a reduced cortisol level at awakening (p = 0.017) after 12 weeks of PE treatment. No apparent effects of ICBT or TAU interventions were seen on diurnal cortisol levels.Conclusions and Message: PE reduced the rate of cortisol level decline across the day in depressed adults. ICBT and TAU treatments had no detectable effects on diurnal cortisol levels. Larger samples are required for the detection and comparison of smaller effects of PE, ICBT and TAU on diurnal cortisol levels.
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