| 1. |
- Abbasi, R, et al.
(författare)
-
Extending the Search for Neutrino Point Sources with IceCube above the Horizon
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 221102-
-
Tidskriftsartikel (refereegranskat)abstract
- Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.
|
|
| 2. |
- Carlsson, Ella, et al.
(författare)
-
Mass composition of the escaping plasma at Mars
- 2006
-
Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 182:2, s. 320-328
-
Tidskriftsartikel (refereegranskat)abstract
- Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite on Mars Express have been analyzed to determine the mass composition of the escaping ion species at Mars. We have examined 77 different ion-beam events and we present the results in terms of flux ratios between the following ion species: CO2+/O+ and O-2(+)/O+. The following ratios averaged over all events and energies were identified: CO2+/O+ = 0.2 and O-2(+)/O+ = 0.9. The values measured are significantly higher, by a factor of 10 for O-2(+)/O+, than a contemporary modeled ratio for the maximum fluxes which the martian ionosphere can supply. The most abundant ion species was found to be O+, followed by O-2(+) and CO2+. We estimate the loss of CO2+ to be 4.0 x 10(24) s(-1) (0.29 kg s(-1)) by using the previous measurements of Phobos-2 in our calculations. The dependence of the ion ratios in relation to their energy ranges we studied, 0.3-3.0 keV, indicated that no clear correlation was found.
|
|
| 3. |
- Hietala, H., et al.
(författare)
-
Supermagnetosonic Jets behind a Collisionless Quasiparallel Shock
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:24, s. 245001-
-
Tidskriftsartikel (refereegranskat)abstract
- The downstream region of a collisionless quasiparallel shock is structured containing bulk flows with high kinetic energy density from a previously unidentified source. We present Cluster multispacecraft measurements of this type of supermagnetosonic jet as well as of a weak secondary shock front within the sheath, that allow us to propose the following generation mechanism for the jets: The local curvature variations inherent to quasiparallel shocks can create fast, deflected jets accompanied by density variations in the downstream region. If the speed of the jet is super(magneto)sonic in the reference frame of the obstacle, a second shock front forms in the sheath closer to the obstacle. Our results can be applied to collisionless quasiparallel shocks in many plasma environments.
|
|
| 4. |
- Horbury, T., et al.
(författare)
-
Cross-scale : A multi-spacecraft mission to study cross-scale coupling in space plasmas
- 2006
-
Ingår i: European Space Agency, (Special Publication) ESA SP. ; , s. 561-568
-
Konferensbidrag (refereegranskat)abstract
- Collisionless astrophysical plasmas exhibit complexity on many scales: if we are to understand their properties and effects, we must measure this complexity. We can identify a small number of processes and phenomena, one of which is dominant in almost every space plasma region of interest: shocks, reconnection and turbulence. These processes act to transfer energy between locations, scales and modes. However, this transfer is characterised by variability and 3D structure on at least three scales: electron kinetic, ion kinetic and fluid. It is the nonlinear interaction between physical processes at these scales that is the key to understanding these phenomena and predicting their effects. However, current and planned multi-spacecraft missions such as Cluster and MMS only study variations on one scale in 3D at any given time - we must measure the three scales simultaneously fully to understand the energy transfer processes. We propose a mission, called Cross-Scale, to study these processes. Cross-Scale would comprise three nested groups, each consisting of up to four spacecraft. Each group would have a different spacecraft separation, at approximately the electron and ion gyroradii, and a larger MHD scale. We would therefore be able to measure variations on all three important physical scales, simultaneously, for the first time. The spacecraft would fly in formation through key regions of near-Earth space: The solar wind, bowshock, magnetosheath, magnetopause and magnetotail.
|
|
| 5. |
- Mackey, Abigail L., et al.
(författare)
-
The influence of anti-inflammatory medication on exercise-induced myogenic precursor cell responses in humans
- 2007
-
Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 103:2, s. 425-431
-
Tidskriftsartikel (refereegranskat)abstract
- The consumption of nonsteroidal anti-inflammatory drugs (NSAIDs) is widespread among athletes when faced with muscle soreness or injury, but the effects of NSAIDs on satellite cell activity in humans are unknown. To investigate this, 14 healthy male endurance athletes (mean peak oxygen consumption 62 ml x kg(-1) x min(-1)) volunteered for the study, which involved running 36 km. They were divided into two groups and received either 100 mg indomethacin per day or placebo. Muscle biopsies collected before the run and on days 1, 3, and 8 afterward were analyzed for satellite cells by immunohistochemistry with the aid of neural cell adhesion molecule (NCAM) and fetal antigen-1 (FA1) antibodies. Muscle biopsies were also collected from untrained individuals for comparison. Compared with preexercise levels, a 27% increase in the number of NCAM+ cells was observed on day 8 postexercise in the placebo group (P < 0.05), while levels remained similar at all time points in the NSAID group. No change was seen in the proportion of FA1+ cells, although lower levels were found in the muscle of endurance-trained athletes compared with untrained individuals (P < 0.05). These results suggest that ingestion of anti-inflammatory drugs attenuates the exercise-induced increase in satellite cell number, supporting the role of the cyclooxygenase pathway in satellite cell activity.
|
|
| 6. |
- Andersson, P, et al.
(författare)
-
Microlubrication effect by laser-textured steel surfaces
- 2007
-
Ingår i: Wear. - 0043-1648 .- 1873-2577. ; 262, s. 369-379
-
Tidskriftsartikel (refereegranskat)abstract
- The beneficial effect on lubrication achieved through microtexturing by laser ablation was investigated. The investigation was based on two independent experimental approaches with oil-lubricated smooth and laser-textured steel surfaces in oscillating sliding contact with a steel ball. Two types of laser-textured patterns of microcavities were studied. It was found that, in comparison with smooth steel surfaces, the laser texturing significantly reduces friction and wear. The most significant improvement in the tribological performance was achieved with an oil of high viscosity combined with a texture comprising a low density of deep microcavities.
|
|
| 7. |
|
|
| 8. |
- Lundberg, Pernilla, et al.
(författare)
-
Osteoclast formation is strongly reduced both in vivo and in vitro in the absence of CD47/SIRPalpha-interaction.
- 2007
-
Ingår i: Biochemical and biophysical research communications. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 352:2, s. 444-8
-
Tidskriftsartikel (refereegranskat)abstract
- Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPalpha) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPalpha-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPalpha strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP)+ osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47-/- mice were strongly reduced, and bones of CD47-/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPalpha interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47-/- mice.
|
|
| 9. |
- Malm, J., et al.
(författare)
-
The Swedish Malignant Middle cerebral artery Infarction Study : long-term results from a prospective study of hemicraniectomy combined with standardized neurointensive care
- 2006
-
Ingår i: Acta Neurologica Scandinavica. - Copenhagen : Munksgaard. - 0001-6314 .- 1600-0404. ; 113:1, s. 25-30
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Hemicraniectomy in patients with malignant middle cerebral artery (mMCA) infarct may be life-saving. The long-term prognosis is unknown.Methods: Patients with mMCA infarct treated with hemicraniectomy between 1998 and 2002 at three hospitals were included. The criterion for surgical intervention was if the patients deteriorated from awake to being responding to painful stimuli only. All patients were followed for at least 1 year. Outcome was defined as alive/dead, walkers/non-walkers or modified Rankin Scale (mRS) score ≤2.Results: Thirty patients were included (median age at stroke onset 49 years, range 17–67 years). Fourteen patients had mMCA infarct on the left side and 16 patients on the right side. Fourteen patients had pupil dilatation before surgery. Hemicraniectomy was performed at a median of 52 h (range 13–235 h) after stroke onset. Nine patients died within 1 month after surgery because of cerebral herniation (n = 6), myocardial infarction (n = 1) or intensive care complications (n = 2). No further deaths occurred during follow-up, which was at median 3.4 years after surgery. Status for the 21 survivors at the last follow-up was: mRS 2 or less (n = 6) and mRS 3–5 (n = 15). The oldest patient with mRS 2 or less was 53 years at stroke onset. Thirteen patients (43%) could walk without substantial aid.Conclusion: The long-term survival after mMCA infarction treated with hemicraniectomy seems to be favourable if the patient survives the acute phase. The outcome as measured with mRS may be better among younger patients.
|
|
