| 1. |
- Alfoeldi, Jessica, et al.
(författare)
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The genome of the green anole lizard and a comparative analysis with birds and mammals
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 477:7366, s. 587-591
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of the amniotic egg was one of the great evolutionary innovations in the history of life, freeing vertebrates from an obligatory connection to water and thus permitting the conquest of terrestrial environments(1). Among amniotes, genome sequences are available for mammals and birds(2-4), but not for non-avian reptiles. Here we report the genome sequence of the North American green anole lizard, Anolis carolinensis. We find that A. carolinensis microchromosomes are highly syntenic with chicken microchromosomes, yet do not exhibit the high GC and low repeat content that are characteristic of avian microchromosomes(2). Also, A. carolinensis mobile elements are very young and diverse-more so than in any other sequenced amniote genome. The GC content of this lizard genome is also unusual in its homogeneity, unlike the regionally variable GC content found in mammals and birds(5). We describe and assign sequence to the previously unknown A. carolinensis X chromosome. Comparative gene analysis shows that amniote egg proteins have evolved significantly more rapidly than other proteins. An anole phylogeny resolves basal branches to illuminate the history of their repeated adaptive radiations.
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| 2. |
- Delley, Diane, et al.
(författare)
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ASTER: Developing a Platform to Achieve Microgravity for Low-Cost Experiments
- 2021
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Ingår i: IAC 2021 Congress Proceedings, 72nd International Astronautical Congress (IAC), Dubai, United Arab Emirates. - : International Astronautical Federation, IAF.
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Konferensbidrag (refereegranskat)abstract
- Microgravity is an important field of research, which is vital for the efficient future utilisation of space. It is possible to undertake microgravity experiments on-orbit, however, this is often well outside the available funding range of low-cost experiments. Microgravity experiments undertaken on sounding rockets are more accessible to low-budget institutions and students, and provide longer periods of sustained microgravity than drop towers and parabolic flights. However, unless stabilised, such experiments cannot achieve true microgravity conditions due to residual external forces, such as the centrifugal force of the rocket’s spin, acting on the experiment. Thus, projects that want to carry out experiments in microgravity conditions would first need to design the platform required to achieve true microgravity, making these projects more complex and time intensive.Project ASTER (Attitude STabilised free falling ExpeRiment) is designing and testing such a platform for microgravity research. ASTER is taking advantage of the extended microgravity period of a sounding rocket flight to test a high performance, low-cost Attitude Control System (ACS) solution capable of providing microgravity conditions for experiments. This would greatly benefit both future satellite projects and sounding rocket experiments which require highly accurate stabilisation and pointing capabilities. The design utilises three reaction wheels controlled by a closed loop system to stabilise a Free Falling Unit - ejected from a sounding rocket - within seconds. The platform will be able to perform slewing manoeuvres and accommodate future experiments on easily adaptable mounting points which allow for on-board sensors and cameras. ASTER will be launched on-board REXUS 30 in March 2022, after which it will be recovered and the obtained results will be published on an open source basis to ensure its future availability to student and other low budget research projects, thereby allowing further improvement, optimisation, and customisation. ASTER is aiming to establish a platform which simplifies the development of microgravity experiments, especially for student projects which often face tight schedules and limited resources. ASTER is being developed as part of the 13th Cycle of the German-Swedish student programme REXUS/BEXUS by students of Luleå University of Technology (LTU) at the Kiruna Space Campus.
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| 3. |
- Lange, Jonathan, et al.
(författare)
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ASTER: Developing a High Performance Attitude Controlled Platform for Low-Cost Experiments
- 2021
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Ingår i: GLEX 2021 Conference Proceedings, IAF Global Space Exploration Conference 2021, St. Petersburg, Russian Federation. - : International Astronautical Federation, IAF.
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Konferensbidrag (refereegranskat)abstract
- An important aspect of the low-cost development of spacecraft components is its verification of the functionality under microgravity conditions. Microgravity is an important field of research, providing a suitable testbed for new technologies, in order to mimic the conditions of such projects. Microgravity experiments undertaken on sounding rockets however, cannot achieve true microgravity conditions unless stabilised due to residual external forces acting on the experiment, such as the rocket’s spin.Project ASTER (Attitude STabilised free falling ExpeRiment) is taking advantage of the extended microgravity period of a sounding rocket flight to test a high performing, low-cost Attitude Control System (ACS) solution. This would greatly benefit both future exploration missions and sounding rocket experiments which require highly accurate stabilisation and pointing capabilities. The proposed design utilises three reaction wheels to stabilise a Free Falling Unit ejected from a sounding rocket within seconds. The platform will be able to perform slewing manoeuvres and accommodate future experiments on easily adaptable mounting points. ASTER will be launched on-board REXUS 30 in March 2022, after which the obtained results will be published on an open source basis to ensure its future availability to student and low budget research projects, thereby allowing further improvement, optimisation, and customisation. ASTER is being developed as part of the 13th Cycle of the German-Swedish student programme REXUS/BEXUS.
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| 4. |
- Pérez Cámara, Flavia, et al.
(författare)
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Project ASTER : True Microgravity during Free-Fall with Attitude Stabilisation
- 2020
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Konferensbidrag (refereegranskat)abstract
- The verification of a spacecraft component’s functionality under microgravity conditions is an important topic for the low-cost development of CubeSat components. The testing and verification of new components is often carried out on technological demonstration missions. In order to reduce the budget and time required, the verification process can also be undertaken on sounding rockets. In order to achieve true microgravity conditions, the testing platform must be entirely stabilised. Most sounding rockets are spin stabilised and, therefore, a centrifugal force acting upon the components remains. This force can be eliminated by ejecting the testing platform on a fully stabilised Free Falling Unit. Available attitude control systems are targeted at orbital flights, and therefore act slowly. Such systems measure their attitude control manoeuvres in orbits rather than minutes or seconds, which is suboptimal as experiments conducted on Free Falling Units are highly constrained by flight time. Taking these requirements into account, the objective of Project ASTER is to design and test a low-cost solution, utilising reaction wheels to stabilise and orientate in a reduced gravity environment. The results of the project will be published on an open source basis to ensure its future availability to student and low budget research projects.
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| 5. |
- Ranieri, V. Marco, et al.
(författare)
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Drotrecogin Alfa (Activated) in Adults with Septic Shock
- 2012
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 366:22, s. 2055-2064
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND There have been conflicting reports on the efficacy of recombinant human activated protein C, or drotrecogin alfa (activated) (DrotAA), for the treatment of patients with septic shock. METHODS In this randomized, double-blind, placebo-controlled, multicenter trial, we assigned 1697 patients with infection, systemic inflammation, and shock who were receiving fluids and vasopressors above a threshold dose for 4 hours to receive either DrotAA (at a dose of 24 mu g per kilogram of body weight per hour) or placebo for 96 hours. The primary outcome was death from any cause 28 days after randomization. RESULTS At 28 days, 223 of 846 patients (26.4%) in the DrotAA group and 202 of 834 (24.2%) in the placebo group had died (relative risk in the DrotAA group, 1.09; 95% confidence interval [CI], 0.92 to 1.28; P = 0.31). At 90 days, 287 of 842 patients (34.1%) in the DrotAA group and 269 of 822 (32.7%) in the placebo group had died (relative risk, 1.04; 95% CI, 0.90 to 1.19; P = 0.56). Among patients with severe protein C deficiency at baseline, 98 of 342 (28.7%) in the DrotAA group had died at 28 days, as compared with 102 of 331 (30.8%) in the placebo group (risk ratio, 0.93; 95% CI, 0.74 to 1.17; P = 0.54). Similarly, rates of death at 28 and 90 days were not significantly different in other predefined subgroups, including patients at increased risk for death. Serious bleeding during the treatment period occurred in 10 patients in the DrotAA group and 8 in the placebo group (P = 0.81). CONCLUSIONS DrotAA did not significantly reduce mortality at 28 or 90 days, as compared with placebo, in patients with septic shock.
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