1,366 research outputs found
Space education in Kiruna, Northern Sweden
International audienceThe town of Kiruna in the north of Sweden has a concentration of space activities and space research with, for example, the Swedish Institute of Space Physics, Esrange, the ESA SalmijÀrvi satellite station, and EISCAT (European Incoherent Scatter Radar) Scientific Association. The Department of Space Science is a joint department between the two most northern universities in Sweden, LuleÄ University of Technology and UmeÄ University in collaboration with the Swedish Institute of Space Physics. It offers a range of education programmes in the space field. There are bachelor and master programmes in space engineering, and a bridging programme for students without a science background from secondary school. The Department also contributes to courses for teachers, Ph.D. courses and secondary school level courses. One masterŽs program and a three week summer course are given entirely in English and welcome international students. Thanks to good cooperation with Esrange students can build and fly experiments on high altitude balloons and sounding rockets and also take a large responsibility for the management of the projects. Close interaction with research and industry is an important part of the education
Clinical and pathophysiological aspects of intrahepatic cholestasis of pregnancy
Objective: The pathogenesis of intrahepatic cholestasis of pregnancy (ICP) involves impaired bile acid and estrogen/progesterone metabolism and excretion based on genetic and environmental factors. In this thesis we evaluated different pathophysiological and clinical aspects of ICP, i.e., serum levels of vitamin D, the morphology of ICP placentas, maternal and fetal outcomes in ICP at a time of active management, and ICP-associated pregnancy conditions.
Methods: In Paper I, we performed an observational study and compared the levels of active vitamin D (1,25-dihydroxy vitamin D3) in women with ICP and normal pregnancies. In Paper II we examined in a prospective case-control study morphological differences of placentas from untreated and ursodeoxycholic acid (UDCA) treated ICP, respectively, and normal pregnancies, by using stereology and systematic random sampling. In paper III, we estimated in a nationwide cohort study of more than 1.2 million singleton births in Sweden between 1997 and 2009 the actual prevalence of ICP and its association with adverse pregnancy and fetal outcomes, using data of the Swedish Medical Birth Registry (MBR). In Paper IV, we assessed in a hospital based retrospective cohort study the risk of emergency cesarean section (CS) and fetal asphyxia in ICP women with spontaneous and induced onset of labor at gestational weeks 37-39, by linkage of the MBR and a local obstetrical database.
Results: We report for the first time that women with ICP have lower levels of active vitamin D. We also show that ICP substantially affects the morphology of the placenta, with increased surface capillary area and syncytial knots. These changes were not observed in UDCA-treated ICP. In our nationwide population based study, we found a previously unknown strong association of ICP with gestational diabetes, preeclampsia and large for gestational age, and that ICP bears an increased risk of moderate prematurity but not of stillbirth at a time of active management. We found that induction of labor in women with ICP in gestational weeks 37-39 in a tertiary Swedish hospital did not increase the risks of emergency CS or fetal asphyxia.
Conclusions: Decreased levels of active vitamin D may contribute to the pathogenesis of ICP. ICP causes morphological changes in the placenta that might be improved by treatment with UDCA. Induction of labor in ICP does not increase the rate of emergency CS. The low risk of stillbirths at a time of modern management of ICP is reassuring but the strong association of ICP with gestational diabetes and preeclampsia needs consideration, e.g., by oral glucose tolerance testing and proper management of possibly coexisting conditions
Space education in Kiruna, Northern Sweden
The town of Kiruna in the north of Sweden has a concentration of space activities and space research with, for example, the Swedish Institute of Space Physics, Esrange, the ESA Salmijärvi satellite station, and EISCAT (European Incoherent Scatter Radar) Scientific Association. The Department of Space Science is a joint department between the two most northern universities in Sweden, Luleå University of Technology and Umeå University in collaboration with the Swedish Institute of Space Physics. It offers a range of education programmes in the space field. There are bachelor and master programmes in space engineering, and a bridging programme for students without a science background from secondary school. The Department also contributes to courses for teachers, Ph.D. courses and secondary school level courses. One master´s program and a three week summer course are given entirely in English and welcome international students. Thanks to good cooperation with Esrange students can build and fly experiments on high altitude balloons and sounding rockets and also take a large responsibility for the management of the projects. Close interaction with research and industry is an important part of the education
Pluricomplex Green and Lempert functions for equally weighted poles
For a domain in , the pluricomplex Green function with
poles is defined as .
When there is only one pole, or two poles in the unit ball, it turns out to be
equal to the Lempert function defined from analytic disks into by . It is known
that we always have . In the more general case where we
allow weighted poles, there is a counterexample to equality due to Carlehed and
Wiegerinck, with equal to the bidisk.
Here we exhibit a counterexample using only four distinct equally weighted
poles in the bidisk. In order to do so, we first define a more general notion
of Lempert function "with multiplicities", analogous to the generalized Green
functions of Lelong and Rashkovskii, then we show how in some examples this can
be realized as a limit of regular Lempert functions when the poles tend to each
other. Finally, from an example where in the case of
multiple poles, we deduce that distinct (but close enough) equally weighted
poles will provide an example of the same inequality. Open questions are
pointed out about the limits of Green and Lempert functions when poles tend to
each other.Comment: 25 page
Consanguineous marriage, prepregnancy maternal characteristics and stillbirth risk: A population-based case-control study
Introduction. Consanguineous marriage is associated with increased risks for congenital anomalies, low birthweight, and other adverse perinatal outcomes. In this population-based, case-control study we investigated the association between consanguineous marriage (first-cousin marriage) and stillbirth risk, using prospectively collected information from prepregnancy visits. Material and methods. From 2007 to 2009, we identified 283 stillbirths (cases) and 2088 randomly selected live control births through prepregnancy visits in rural Golestan, Iran. The associations between consanguinity and prepregnancy maternal characteristics and stillbirth risk were examined using multivariate logistic regression. Results. The rate of consanguineous marriage was 19.4% among cases and 13.6% among controls. Consanguinity was associated with increased stillbirth risk [odds ratio (OR) 1.53; 95% CI 1.10-2.14]. The association was significantly increased for preterm stillbirth (< 37 gestational weeks) (OR 2.43; 95% CI 1.46-4.04) but not for term stillbirth (℠37 weeks) (OR 1.14; 95% CI 0.75-1.74). Low and high maternal age, underweight, obesity, nulliparity, a history of infertility or miscarriage, previous obstetric complications (preeclampsia, preterm delivery, and stillbirth in previous pregnancies) were also associated with increased stillbirth risks. Conclusions. Consanguineous marriage is associated with increased risk of stillbirth, particularly preterm stillbirth. Findings for other maternal risk factors for stillbirth in rural Iran are consistent with previously reported findings from high-income countries. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology
Taxon composition and food-web structure in a morphometric gradient of Baltic Sea land-uplift bays
Convergence and multiplicities for the Lempert function
Given a domain , the Lempert function is a
functional on the space Hol (\D,\Omega) of analytic disks with values in
, depending on a set of poles in . We generalize its definition
to the case where poles have multiplicities given by local indicators (in the
sense of Rashkovskii's work) to obtain a function which still dominates the
corresponding Green function, behaves relatively well under limits, and is
monotonic with respect to the indicators. In particular, this is an improvement
over the previous generalization used by the same authors to find an example of
a set of poles in the bidisk so that the (usual) Green and Lempert functions
differ.Comment: 24 pages; many typos corrected thanks to the referee of Arkiv for
Matemati
Time-resolved generation of membrane potential by ba3 cytochrome c oxidase from Thermus thermophilus coupled to single electron injection into the O and OH states
peer-reviewedTwo electrogenic phases with characteristic times of ~ 14 ÎŒs and ~ 290 ÎŒs are resolved in the kinetics of membrane potential generation coupled to single-electron reduction of the oxidized ârelaxedâ O state of ba3 oxidase from T. thermophilus (O â E transition). The rapid phase reflects electron redistribution between CuA and heme b. The slow phase includes electron redistribution from both CuA and heme b to heme a3, and electrogenic proton transfer coupled to reduction of heme a3. The distance of proton translocation corresponds to uptake of a proton from the inner water phase into the binuclear center where heme a3 is reduced, but there is no proton pumping and no reduction of CuB. Single-electron reduction of the oxidized âunrelaxedâ state (OH â EH transition) is accompanied by electrogenic reduction of the heme b/heme a3 pair by CuA in a âfastâ phase (~ 22 ÎŒs) and transfer of protons in âmiddleâ and âslowâ electrogenic phases (~ 0.185 ms and ~ 0.78 ms) coupled to electron redistribution from the heme b/heme a3 pair to the CuB site. The âmiddleâ and âslowâ electrogenic phases seem to be associated with transfer of protons to the proton-loading site (PLS) of the proton pump, but when all injected electrons reach CuB the electronic charge appears to be compensated by back-leakage of the protons from the PLS into the binuclear site. Thus proton pumping occurs only to the extent of ~ 0.1 H+/eâ, probably due to the formed membrane potential in the experiment.ACCEPTEDpeer-reviewe
Specific inhibition of proton pumping by the T315V mutation in the K channel of cytochrome ba3 from Thermus thermophilus
Cytochrome ba3 from Thermus thermophilus belongs to the B family of hemeâcopper oxidases and pumps protons across the membrane with an as yet unknown mechanism. The K channel of the A family hemeâcopper oxidases provides delivery of a substrate proton from the internal water phase to the binuclear hemeâcopper centre (BNC) during the reductive phase of the catalytic cycle, while the D channel is responsible for transferring both substrate and pumped protons. By contrast, in the B family oxidases there is no D-channel and the structural equivalent of the K channel seems to be responsible for the transfer of both categories of protons. Here we have studied the effect of the T315V substitution in the K channel on the kinetics of membrane potential generation coupled to the oxidative half-reaction of the catalytic cycle of cytochrome ba3. The results suggest that the mutated enzyme does not pump protons during the reaction of the fully reduced form with molecular oxygen in a single turnover. Specific inhibition of proton pumping in the T315V mutant appears to be a consequence of inability to provide rapid (ÏâŻ~âŻ100âŻÎŒs) reprotonation of the internal transient proton donor(s) of the K channel. In contrast to the A family, the K channel of the B-type oxidases is necessary for the electrogenic transfer of both pumped and substrate protons during the oxidative half-reaction of the catalytic cycle.Peer reviewe
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