| 1. |
- Bonanni, Valentina, et al.
(författare)
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First order reversal curve analysis of graded anisotropy FePtCu films
- 2010
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 97:20
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Tidskriftsartikel (refereegranskat)abstract
- The reversal mechanisms of graded anisotropy FePtCu films have been investigated by alternating gradient magnetometer (AGM) and magneto-optical Kerr effect (MOKE) measurements with first-order reversal curve (FORC) techniques. The AGM-FORC analysis, which clearly shows the presence of soft and hard components, is unable to resolve how these phases are distributed throughout the film thickness. MOKE-FORC measurements, which preferentially probe the surface of the film, reveal that the soft components are indeed located toward the top surface. Combining AGM-FORC with the inherent surface sensitivity of MOKE-FORC analysis allows for a comprehensive analysis of heterogeneous systems such as graded materials.
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| 2. |
- Bonetti, Stefano, 1982-, et al.
(författare)
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Experimental evidence of self-localized and propagating spin wave modes in obliquely magnetized current-driven magnetic nanocontacts
- 2010
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 105:21, s. 217204-
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Tidskriftsartikel (refereegranskat)abstract
- Through detailed experimental studies of the angular dependence of spin wave excitations in nanocontact-based spin-torque oscillators, we demonstrate that two distinct spin wave modes can be excited, with different frequency, threshold currents, and frequency tunability. Using analytical theory and micromagnetic simulations we identify one mode as an exchange-dominated propagating spin wave, and the other as a self-localized nonlinear spin wave bullet. Wavelet-based analysis of the simulations indicates that the apparent simultaneous excitation of both modes results from rapid mode hopping induced by the Oersted field.
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| 3. |
- Cheraghchi, M., et al.
(författare)
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Approximating Linear Threshold Predicates
- 2010
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Ingår i: Lecture Notes in Computer Science. 13th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems, APPROX 2010 and 14th International Workshop on Randomization and Computation, RANDOM 2010, Barcelona, 1-3 September 2010. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783642153686 ; 6302, s. 110-123
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Konferensbidrag (refereegranskat)abstract
- We study constraint satisfaction problems on the domain {-1,1}, where the given constraints are homogeneous linear threshold predicates. That is, predicates of the form sgn(w1 x1+⋯+wn x n ) for some positive integer weights w 1, ..., w n . Despite their simplicity, current techniques fall short of providing a classification of these predicates in terms of approximability. In fact, it is not easy to guess whether there exists a homogeneous linear threshold predicate that is approximation resistant or not. The focus of this paper is to identify and study the approximation curve of a class of threshold predicates that allow for non-trivial approximation. Arguably the simplest such predicate is the majority predicate sgn(x 1+⋯+xn ), for which we obtain an almost complete understanding of the asymptotic approximation curve, assuming the Unique Games Conjecture. Our techniques extend to a more general class of "majority-like" predicates and we obtain parallel results for them. In order to classify these predicates, we introduce the notion of Chow-robustness that might be of independent interest.
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| 4. |
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| 5. |
- Elmlund, Dominika, 1981-, et al.
(författare)
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Ab initio structure determination from electron microscopic images of single molecules coexisting in different functional states
- 2010
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 18:7, s. 777-786
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Tidskriftsartikel (refereegranskat)abstract
- We have developed methods for ab initio three-dimensional (3D) structure determination from projection images of randomly oriented single molecules coexisting in multiple functional states, to aid the study of complex samples of macromolecules and nanoparticles by electron microscopy (EM). New algorithms for the determination of relative 3D orientations and conformational state assignment of single-molecule projection images are combined with well-established techniques for alignment and statistical image analysis. We describe how the methodology arrives at homogeneous groups of images aligned in 3D and discuss application to experimental EM data sets of the Escherichia coli ribosome and yeast RNA polymerase II.
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| 6. |
- Fang, Yeyu, et al.
(författare)
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FORC studies of exchange biased NiFe in L1_0(111) FePt-based spin valve
- 2010
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Ingår i: Journal of Physics Conference Series. - BRISTOL : IOP Publishing. - 1742-6588 .- 1742-6596. ; 200:7, s. 072002-
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Tidskriftsartikel (refereegranskat)abstract
- We use First-Order Reversal Curves (FORC) to study the switching distribution and exchange bias in L10 (111) FePt-based spin valves with a layer structure of Ta (6)/Pt (3)/L10 (111) Fe53Pt47 (20)/Co50Fe50 (1.5)/Cu (4.5)/Co50Fe50 (2)/Ni80Fe20 (3) (in nm). We find that the switching of the free layer magnetization is strongly influence by the magnetic state of the FePt/CoFe fixed layer, as evidenced by tunable coercivity and exchange bias fields.
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| 7. |
- Flisberg, Anders, 1958, et al.
(författare)
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Does indomethacin for closure of patent ductus arteriosus affect cerebral function?
- 2010
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 99:10, s. 1493-1497
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To study whether indomethacin used in conventional dose for closure of patent ductus arteriosus affects cerebral function measured by Electroencephalograms (EEG) evaluated by quantitative measures. Study design: Seven premature neonates with haemodynamically significant persistent ductus arteriosus were recruited. EEG were recorded before, during and after an intravenous infusion of 0.2 mg/kg indomethacin over 10 min. The EEG was analysed by two methods with different degrees of complexity for the amount of low-activity periods (LAP, "suppressions") as an indicator of affection of cerebral function. Results: Neither of the two methods identified any change in the amount of LAPs in the EEG as compared to before the indomethacin infusion. Conclusion: Indomethacin in conventional dose for closure of patent ductus arteriosus does not affect cerebral function as evaluated by quantitative EEG.
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| 8. |
- Flisberg, Anders, 1958, et al.
(författare)
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EEG and spectral edge frequency : analysis in posthypoxic newborn piglets
- 2010
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Ingår i: Neuro - endocrinology letters. - : Brain Research Promotion. - 0172-780X. ; 31:2, s. 181-186
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the frequency content of the electroencephalogram (EEG) during recovery after a severe hypoxic insult in newborn piglets. METHODS: EEG was continuously monitored in nine newborn piglets exposed to a severe hypoxic period. Power spectra in five frequency bands were calculated using Fourier transformation. Spectral edge frequency 90 (SEF90) was defined as the frequency below which 90% of the power in the EEG was located. The piglets were divided into two groups; Group 1 represented piglets with some EEG recovery and Group 2 represented piglets without any EEG recovery. RESULTS: The recovery of the EEG in Group 1 had the same time course in all frequency bands. SEF90 indicates recovery earlier than the value of total power. But SEF90 also signals activity in the EEGs that were almost completely suppressed. When SEF90 was calculated during periods of periodic EEG activity during the very early phase of recovery, the values fell within the same range as during the control period. CONCLUSION: Spectral analysis of continuous EEG in newborn piglets exposed to very severe hypoxia showed that no specific frequency band of the EEG preceded the other ones during recovery. The results of the SEF90 measure, demonstrates the need for critical analysis of the raw EEG before any reliable estimation of cerebral function can be made.
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| 9. |
- Holmgren, Kristina, 1955, et al.
(författare)
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The association between poor organizational climate and high work commitments, and sickness absence in a general population of women and men
- 2010
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Ingår i: Journal of Occupational and Environmental Medicine. - : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948. ; 52:12, s. 1179-1185
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the association between organizational climate and work commitment, and sickness absence in a general population of workers and consecutively selected employed sick-listed. Methods: Questionnaire data used in this cross-sectional study consisted of two cohorts: (1) randomly selected individuals in a general working population cohort (2763) and (2) consecutively selected employed sick-listed cohort (3044) for more than 14 days over 2 months. Results: Poor organizational climate was associated with increased odds of belonging to the employed sick-listed cohort among both women and men, while high work commitments were associated with increased odds only among women. The increased adjusted odds ratio for the combinations of poor organizational climate and high work commitment was 1.80 (confidence interval 1.36 to 2.37) among women and 2.74 (confidence interval 1.84 to 4.08) among men. Conclusions: These results support the magnitude of combining organizational climate and work commitment.
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| 10. |
- Jacksén, Johan, et al.
(författare)
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Capillary electrophoresis separation and matrix-assisted laser desorption/ionization mass spectrometry characterization of bovine serum albumin fluorescein isothiocyanate conjugates
- 2010
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 878:15-16, s. 1125-1134
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Tidskriftsartikel (refereegranskat)abstract
- A protocol using enzymatic digestion, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and capillary electrophoresis with laser induced fluorescence detection (CE-LIF) for the investigation of the binding of the fluorescent contact allergen fluorescein isothiocyanate (FITC) to the 66 kDa large protein bovine serum albumin (BSA), as a model system for protein-hapten binding in the skin, is presented. Mass spectra of BSA-FITC digestions, using trypsin and chymotrypsin, respectively, provided sequence coverage of 97%. To investigate the number of FITC-bound peptides using CE-LIF separation, three different buffer salts at four different pH levels were evaluated. The use of 20 mM sodium citrate pH 6.5 as well as 20 mM sodium phosphate pH 6.5 or pH 7.5 as background electrolyte revealed high numbers of peptides with at least one bound FITC. The effect of the electrolyte counter ion on MALDI-MS was investigated and was found to have effect on the MALDI spectra signal-to-noise (S/N) at 50 mM but not at 10 m M. Of the 60 theoretical FITC-binding sites in BSA this MALDI-MS protocol presents 30 defined. 28 possible and 2 non-binding sites for FITC. (C) 2010 Elsevier B.V. All rights reserved.
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