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Search Results: 1 - 10 of 826 matches for " Larsson "
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Substance Identification in Anti-Doping Control by Means of Mass Spectrometry. Data Reduction and Decision Criteria  [PDF]
Mats Larsson
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2011, DOI: 10.4236/jasmi.2011.12003
Abstract: A real doping case for which the national-level reviewing body deemed it probable that a misidentification of the national-level athlete’s sample occurred at the WADA accredited laboratory, thus making the athlete in this case strictly anonymous, is used to discuss criteria for data reduction and tolerance windows in GC-MS and LC-MS/MS. Stricter criteria for data reduction would remedy the present ambiguities.
Lattice Enthalpy Drives Hubbard U to Zero  [PDF]
Sven Larsson
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.46A007
Abstract:

In the equation U = IA for the Mott energy, the electron-hole interaction of the successor state is missing. Adding the attractive term, the energy for disproportionation (Hubbard U), may adopt any sign. The missing term is related to the Born effect, the Madelung correction and the Lattice Enthalpy.

Cardiac Self-Efficacy and Fatigue One Year Post-Myocardial Infarction  [PDF]
Ulla Fredriksson-Larsson
Open Journal of Nursing (OJN) , 2019, DOI: 10.4236/ojn.2019.94036
Abstract: Background: Patients and clinicians report that fatigue post-myocardial infraction (MI) is a bothersome symptom during recovery. Aim: The objective of this study was to explore whether there is a relationship between fatigue, cardiac self-efficacy, stress, breathlessness and physical activity one year post-MI. Method: Data were collected from a sample of patients diagnosed with MI one year earlier (n = 125) who responded to a questionnaire package measuring fatigue, cardiac self-efficacy, physical activity and the symptoms breathlessness and stress. Correlation and regression analyses were preformed to evaluate which factors were related to fatigue. Results: The results showed that cardiac self-efficacy was associated with fatigue (r = 0.611, p = 0.01) and the regression model, controlling for breathlessness and stress, showed an explained variance of 72% one year post-MI. Physical activity was not significant in this model and did not predict fatigue during this time period. Conclusion: Post-MI fatigue-relief support should rely not only on identification of fatigue and other concurrent symptoms, but also on identification of cardiac self-efficacy.
Phonons in Lattice and Structural Dynamics
Sven Larsson
Advances in Condensed Matter Physics , 2010, DOI: 10.1155/2010/627452
Abstract: The critical temperature ( ) of superconductivity in compounds is generally lower smaller with alkali atoms (A). Furthermore decreases with applied pressure. In the BCS model, these trends are explained by the lower density of states at the Fermi level for a decreased lattice constant (R). There is more than one counterexample, however, suggesting that BCS does not give the whole truth. The most important one is that the compound with the largest lattice constant, , is not superconducting at all at ambient pressure. In this paper we derive a novel model where a negative lattice contribution to Hubbard U, proportional to 1/R, is taken into account. It is possible to explain why compounds with A = Li, and Na have a low or are not superconducting at all, and why is superconducting only at applied pressure and then with the highest of all alkali fullerides. It is concluded that the density of states mechanism derived in the BCS model is in doubt. Nevertheless superconductivity in depends on electron-phonon coupling. The dominating phonon is the bond stretching phonon, a breathing phonon for the whole fullerene molecular ion. 1. Introduction The discoveries of conductivity and superconductivity (SC) in and were great events in science during the 1990s [1–5]. SC was later discovered in a number of other compounds, where A stand for alkali atoms: Li, Na, K, Rb, or Cs. Generally, increase of the lattice constant leads to a higher critical temperature . Some of the compounds (A = Li, Na) with the smallest lattice constants are not superconducting [6–8]. Only fullerides have proven to be superconducting (SC). Remarkably, the compound with the highest lattice constant does not follow this trend [9–11]. Disorder-free is an antiferromagnetic insulator at ambient pressure. However, already at the quite modest pressure of 3?kbar ( 3000?atm), it turns into a superconductor (SC) with the highest known for any fulleride [9–11]. At temperatures above passes directly into a semiconducting and antiferromagnetic phase. This system thus needs an explanation model which is not depending on the existence of free electrons, as in the BCS model. Takabayashi et al. further point out [11] that transfer from SC to antiferromagnetic phase appears to be “purely electronic”, thus seemingly explicable without resorting to nuclear dynamics. There are a number of peculiarities in experimental data in general, as summarized by Gunnarsson [12], Rosseinsky [13], Margadonna and Prassides [14], and Iwasa and Takenobu [15]. A widely accepted approach is to treat the metallic alkali fullerides
Mixed valence model for superconductivity
Larsson, Sven;
Brazilian Journal of Physics , 2003, DOI: 10.1590/S0103-97332003000400022
Abstract: superconductivity often occurs in crystals with one active electron per site with charge density wave (cdw) or spin density wave (sdw) as 'mother state'. it is proposed that superconductivity is possible when the differences in equilibrium geometry and energy between the diabatic cdw and sdw states are so small that there is interaction between them via the zero point vibrations. electron pairing in real space is directly related to oxidation states being different in two units. three valence states in succession have to be stable (ground state or low-energy excited states) and we therefore refer to this mixed valence model as the mv-3 model. examples are chosen from bismuthates, cuprates, and fullerides. the theory is simple and straightforward and offers solutions to other important problems as well, for example for a3c60(a = k; rb), that (1) there are no magnetic moments in crystal phase, and (2) that these systems are superconducting metals while a4c60 are insulators.
H gre utbildning som politiskt instrument
Katarina Larsson
Utbildning & Demokrati : Tidsskrift f?r Didaktik och Utbildningspolitik , 2009,
Abstract:
Perspectives on the adoption of emergency contraceptive pills as a new contraceptive method
Larsson Margareta
Indian Journal of Medical Sciences , 2007,
Abstract:
Why do fish school?
Matz LARSSON
Current Zoology , 2012,
Abstract: Synchronized movements (schooling) emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ (LLO) of a predator. Moreover, prey-fish moving close to each other may blur the electro-sensory perception of predators. The aim of this review is to explore mechanisms associated with synchronous swimming that may have contributed to increased adaptation and as a consequence may have influenced the evolution of schooling. The evolutionary development of the inner ear and the LLO increased the capacity to detect potential prey, possibly leading to an increased potential for cannibalism in the shoal, but also helped small fish to avoid joining larger fish, resulting in size homogeneity and, accordingly, an increased capacity for moving in synchrony. Water-movements and incidental sound produced as by-product of locomotion (ISOL) may provide fish with potentially useful information during swimming, such as neighbour body-size, speed, and location. When many fish move close to one another ISOL will be energetic and complex. Quiet intervals will be few. Fish moving in synchrony will have the capacity to discontinue movements simultaneously, providing relatively quiet intervals to allow the reception of potentially critical environmental signals. Besides, synchronized movements may facilitate auditory grouping of ISOL. Turning preference bias, well-functioning sense organs, good health, and skillful motor performance might be important to achieving an appropriate distance to school neighbors and aid the individual fish in reducing time spent in the comparatively less safe school periphery. Turning preferences in ancestral fish shoals might have helped fish to maintain groups and stay in formation, reinforcing aforementioned predator confusion mechanisms, which possibly played a role in the lateralization of the vertebrate brain [Current Zoology 58 (1): 116–128, 2012].
A Simple Anisotropic Mesh-Refinement Strategy for Triangular Elements in 2D
Fredrik Larsson
ISRN Applied Mathematics , 2012, DOI: 10.5402/2012/134097
Abstract:
Research at the Unit of Lung and Allergy research at Karolinksa Intitutet, Stockholm, Sweden
Kjell Larsson
European Respiratory Review , 2008,
Abstract:
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