| 11. |
- Edberg, Niklas J. T., et al.
(författare)
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Simultaneous measurements of Martian plasma boundaries by Rosetta and Mars Express
- 2009
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Ingår i: Planetary and Space Science. - : Elsevier BV. - 0032-0633 .- 1873-5088. ; 57:8-9, s. 1085-1096
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Tidskriftsartikel (refereegranskat)abstract
- We present the first two-spacecraft near-simultaneous observations of the Martian bow shock (BS), magnetic pileup boundary (MPB) and photo-electron boundary (PEB) obtained by the plasma instruments onboard Rosetta and Mars Express during the Rosetta Mars fly by on February 25, 2007. Our observations are compared with shape models for the BS and MPB derived from previous statistical studies. The MPB is found at its expected position but the BS for this event is found significantly closer to the planet than expected for the rather slow and moderately dense solar wind. Cross-calibration of the density measurements on the two spacecraft gives a density profile through the magnetosheath, indicating an increasing solar wind flux during the Rosetta passage which is consistent with the multiple BS crossings at the Rosetta exit.
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| 12. |
- Edberg, Niklas, et al.
(författare)
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Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment
- 2009
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 27:12, s. 4533-4545
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Tidskriftsartikel (refereegranskat)abstract
- We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX) on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during similar to 24 h in the combined data set from both spacecraft after Rosetta's closest approach to Mars on 25 February 2007. The bow shock and magnetic pileup boundary are coincidently observed by MEX to become asymmetric in their shapes. The fortunate orbit of MEX at this time allows a study of the inbound boundary crossings on one side of the planet and the outbound crossings on almost the opposite side, both very close to the terminator plane. The solar wind and interplanetary magnetic field (IMF) downstream of Mars are monitored through simultaneous measurements provided by Rosetta. Possible explanations for the asymmetries are discussed, such as crustal magnetic fields and IMF direction. In the same interval, during the high solar wind pressure pulse, MEX observations show an increased amount of escaping planetary ions from the polar region of Mars. We link the high pressure solar wind with the observed simultaneous ion outflow and discuss how the pressure pulse could also be associated with the observed boundary shape asymmetry.
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| 13. |
- Ekberg, Olle, et al.
(författare)
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An In Vitro Model for Studying Neuromuscular Transmission in the Mouse Pharynx.
- 2009
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Ingår i: Dysphagia. - : Springer Science and Business Media LLC. - 1432-0460 .- 0179-051X. ; 24, s. 32-39
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Tidskriftsartikel (refereegranskat)abstract
- The muscles of the pharynx are controlled by networks of neurons under the control of specific regions in the brain stem, which have been fairly well studied. However, the transmission between these neurons and the pharyngeal muscles, at the motor end plates, is less well understood. Therefore, an in vitro model for the study of neuromuscular transmission in the pharyngeal muscle of the mouse was developed. Ring preparations from the inferior constrictor and the cricopharyngeus muscles were isolated and mounted for isometric force recording at physiologic temperature. Preparations from the diaphragm and the soleus muscles were examined in parallel. The muscles were stimulated at supramaximal voltage with short tetani at 100 Hz. Following direct stimulation of the muscle fibers, using a longer pulse duration, the rate of force development of the pharyngeal muscles was similar to that of the diaphragm and faster than that of the soleus muscle. By varying the duration of the stimulation pulses, conditions where the nerve-mediated activation contributed to a major extent of the contractile responses were identified. Gallamine completely inhibited the nerve-mediated responses. In separate experiments the dose dependence of gallamine inhibition was examined, showing similar sensitivity in the inferior pharyngeal constrictor compared to the diaphragm and soleus muscles. We conclude that reproducible contractile responses with an identifiable nerve-induced component can be obtained from the mouse inferior pharyngeal constrictor. The pharyngeal muscles have contractile characteristics similar to those of the faster diaphragm. The sensitivity to the neuromuscular blocking agent gallamine of the inferior pharyngeal constrictor was in the same concentration range as that of the diaphragm and soleus muscles.
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| 14. |
- Eriksson, Anders, et al.
(författare)
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Contrary Arguments in Paul
- 2002
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Ingår i: Rhetorical Criticism and the Bible: Essays from the 1998 Florence Conference.. - 1841270938 ; , s. 348-367
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Bokkapitel (refereegranskat)
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| 15. |
- Eriksson, Anders, 1975, et al.
(författare)
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Direct Transmission Detection of Tunable Mechanical Resonance in an Individual Carbon Nanofiber Relay
- 2008
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- A direct on-chip transmission measurement of the resonance frequency of an individual singly clamped carbon nanofiber relay is reported. The experimental results are in good agreement with a small signal model and show the expected tuning of the resonance frequency with changing bias voltage.
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| 16. |
- Eriksson, Anders, et al.
(författare)
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RPC-LAP : The Rosetta Langmuir probe instrument
- 2007
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 128:04-jan, s. 729-744
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Forskningsöversikt (refereegranskat)abstract
- The Rosetta dual Langmuir probe instrument, LAP, utilizes the multiple powers of a pair of spherical Langmuir probes for measurements of basic plasma parameters with the aim of providing detailed knowledge of the outgassing, ionization, and subsequent plasma processes around the Rosetta target comet. The fundamental plasma properties to be studied are the plasma density, the electron temperature, and the plasma flow velocity. However, study of electric fields up to 8 kHz, plasma density fluctuations, spacecraft potential, integrated UV flux, and dust impacts is also possible. LAP is fully integrated in the Rosetta Plasma Consortium (RPC), the instruments of which together provide a comprehensive characterization of the cometary plasma.
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| 17. |
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| 18. |
- Eriksson, Johannes, et al.
(författare)
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Probing growth defects inside nanowires
- 2006
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Ingår i: Book of abstracts: Intl Conf on Nanosci and Technol, Basel, Switzerland (2006).
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Konferensbidrag (refereegranskat)
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| 19. |
- Eriksson, Katarina, 1977-
(författare)
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Spelar adressen någon roll? : En studie av områdeseffekter på medborgares politiska deltagande
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study is to describe and explain (individual level) public political participation, with particular focus on the significance of the local, geographical context. Studies of political participation have traditionally focused on individual level explanations. Here, however, the question of the significance of place, is also raised i.e. does place have an effect on the probability of the individual to take political action? Such causal relationships are known as contextual (or neighbourhood) effects. These occur when contextual factors affect individual behaviour so that it varies systematically between different contexts, even after controlling for individual level predictors. Although empirical research has been lacking, there is a widespread assumption that place of residence can have both positive and negative effects on outcomes at the level of the individual. This is the case especially with regard to urban residential segregation, which is believed to cause self-generating, negative effects on the political engagement of citizens. My line of argument is that contextual effects cannot be taken for granted; rather they must be tested empirically in a systematic way, using individual level data and appropriate techniques. Political participation is operationalised in terms of: voting in local elections, contacting local officials, and participating in manifestations. The local, geographical context is operationalised in two ways; as Swedish municipalities and as city districts. The latter is done using case studies of two Swedish cities; Umeå, a medium-sized town with moderate socioeconomic segregation, and Göteborg, a large city with extensive polarisation. Survey data is used and analysed by means of multilevel analysis, a technique developed especially for hierarchical data and contextual analysis of individual level outcomes. The results do not provide strong support for the hypothesis of contextual effects on public political participation. There are, in several cases, strong, bivariate relationships between socioeconomic composition and political participation at the aggregate level. However, this is not confirmed in analyses of individual level data. The variation between individuals residing in different places is significant in only one case; when the context is operationalised as municipalities and the dependent variable is participation in manifestations. This variation cannot, however, be explained neither by individual level SES/political engagement nor by socioeconomic composition at the municipal level. An analysis of crosslevel interactions shows that employed persons residing in affluent districts of Göteborg have a higher probability to vote and to participate in contacting than employed persons living in poor neighbourhoods. Similarly, individuals with an immigrant background living in affluent districts in Göteborg are more likely to vote than those living in poor areas. These results give some support for the hypothesis of contextual effects on political participation. However, as the number of observations in this particular analysis is very small, the results are not robust and, consequently, must be interpreted with caution. In order to identify relevant individual level predictors, the SES and CV-models are applied. The results indicate that socioeconomic variables such as employment status and education are important predictors of voting. However, when it comes to contacting officials and participating in manifestations, socio-political resources such as political engagement and organisational membership are better as predictors of political participation.
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| 20. |
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