| 1. |
- Patterson, Allison, et al.
(författare)
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Foraging range scales with colony size in high-latitude seabirds
- 2022
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 32:17, s. 3800-3807
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Tidskriftsartikel (refereegranskat)abstract
- Density-dependent prey depletion around breeding colonies has long been considered an important factor controlling the population dynamics of colonial animals.1, 2, 3, 4 Ashmole proposed that as seabird colony size increases, intraspecific competition leads to declines in reproductive success, as breeding adults must spend more time and energy to find prey farther from the colony.1 Seabird colony size often varies over several orders of magnitude within the same species and can include millions of individuals per colony.5,6 As such, colony size likely plays an important role in determining the individual behavior of its members and how the colony interacts with the surrounding environment.6 Using tracking data from murres (Uria spp.), the world’s most densely breeding seabirds, we show that the distribution of foraging-trip distances scales to colony size0.33 during the chick-rearing stage, consistent with Ashmole’s halo theory.1,2 This pattern occurred across colonies varying in size over three orders of magnitude and distributed throughout the North Atlantic region. The strong relationship between colony size and foraging range means that the foraging areas of some colonial species can be estimated from colony sizes, which is more practical to measure over a large geographic scale. Two-thirds of the North Atlantic murre population breed at the 16 largest colonies; by extrapolating the predicted foraging ranges to sites without tracking data, we show that only two of these large colonies have significant coverage as marine protected areas. Our results are an important example of how theoretical models, in this case, Ashmole’s version of central-place-foraging theory, can be applied to inform conservation and management in colonial breeding species.
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| 2. |
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| 3. |
- Caesar, C., et al.
(författare)
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Beyond the neutron drip line: The unbound oxygen isotopes O-25 and O-26
- 2013
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 88:3
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Tidskriftsartikel (refereegranskat)abstract
- The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.
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| 4. |
- Toor, Salman, et al.
(författare)
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SNIC Science Cloud (SSC): A national-scale cloud infrastructure for Swedish academia
- 2017
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Ingår i: Proceedings - 13th IEEE International Conference on eScience, eScience 2017. - Los Alamitos, CA : IEEE Computer Society. ; , s. 219-227, s. 219-227
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Konferensbidrag (refereegranskat)abstract
- The cloud computing paradigm have fundamentally changed the way computational resources are being offered. Although the number of large-scale providers in academia is still relatively small, there is a rapidly increasing interest and adoption of cloud Infrastructure-as-a-Service in the scientific community. The added flexibility in how applications can be implemented compared to traditional batch computing systems is one of the key success factors for the paradigm, and scientific cloud computing promises to increase adoption of simulation and data analysis in scientific communities not traditionally users of large scale e-Infrastructure, the so called long tail of science. In 2014, the Swedish National Infrastructure for Computing (SNIC) initiated a project to investigate the cost and constraints of offering cloud infrastructure for Swedish academia. The aim was to build a platform where academics could evaluate cloud computing for their use-cases. SNIC Science Cloud (SSC) has since then evolved into a national-scale cloud infrastructure based on three geographically distributed regions. In this article we present the SSC vision, architectural details and user stories. We summarize the experiences gained from running a nationalscale cloud facility into ten simple rules for starting up a science cloud project based on OpenStack. We also highlight some key areas that require careful attention in order to offer cloud infrastructure for ubiquitous academic needs and in particular scientific workloads.
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| 5. |
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| 6. |
- Tinnert, Jon, et al.
(författare)
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Population genetic structure, differentiation, and diversity in Tetrix subulata pygmy grasshoppers : roles of population size and immigration
- 2016
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6:21, s. 7831-7846
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity within and among populations and species is influenced by complex demographic and evolutionary processes. Despite extensive research, there is no consensus regarding how landscape structure, spatial distribution, gene flow, and population dynamics impact genetic composition of natural populations. Here, we used amplified fragment length polymorphisms (AFLPs) to investigate effects of population size, geographic isolation, immigration, and gene flow on genetic structure, divergence, and diversity in populations of Tetrix subulata pygmy grasshoppers (Orthoptera: Tetrigidae) from 20 sampling locations in southern Sweden. Analyses of 1564 AFLP markers revealed low to moderate levels of genetic diversity (PPL=59.5-90.1; Hj=0.23-0.32) within and significant divergence among sampling localities. This suggests that evolution of functional traits in response to divergent selection is possible and that gene flow is restricted. Genetic diversity increased with population size and with increasing proportion of long-winged phenotypes (a proxy of recent immigration) across populations on the island of oland, but not on the mainland. Our data further suggested that the open water separating oland from the mainland acts as a dispersal barrier that restricts migration and leads to genetic divergence among regions. Isolation by distance was evident for short interpopulation distances on the mainland, but gradually disappeared as populations separated by longer distances were included. Results illustrate that integrating ecological and molecular data is key to identifying drivers of population genetic structure in natural populations. Our findings also underscore the importance of landscape structure and spatial sampling scheme for conclusions regarding the role of gene flow and isolation by distance.
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| 7. |
- Gabrielsson, Jon, et al.
(författare)
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Multivariate methods in the development of a new tablet formulation : optimization and validation
- 2004
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Ingår i: Drug Development and Industrial Pharmacy. - New York : M. Dekker. - 0363-9045 .- 1520-5762. ; 30:10, s. 1037-1049
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study of the development of a tablet formulation approximately 100 excipients were characterized in screening experiments using multivariate design. Acceptable values for important responses were obtained with some of the formulations. The relationships between the properties of the excipients and the responses were evaluated using PLS. In this study additional experiments were performed in order to validate models obtained from the screening study and to find a formulation of suitable composition with desired tablet properties. A formulation with the desired disintegration time was found with the additional experiments and the agreement between observed and predicted values was fair for the tablets that did disintegrate. A limitation of this study was that tablets from four experiments did not disintegrate within the set time limit. The lack of agreement between observed and predicted values of these four experiments was probably due to the nature of one of the factors in the design. Considering the reduced experimental design the results are still encouraging.
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| 8. |
- Gabrielsson, Jon, et al.
(författare)
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Multivariate Methods in the Development of a New Tablet Formulation : Excipient Mixtures and Principal Properties
- 2006
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Ingår i: Drug Development and Industrial Pharmacy. - New York : M. Dekker. - 0363-9045 .- 1520-5762. ; 32:1, s. 7-20
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Tidskriftsartikel (refereegranskat)abstract
- A tablet formulation for direct compression has previously been studied using multivariate design. An optimization study of one of the most important tablet properties, disintegration time, revealed that excipients with Principal Properties (PP's) that were predicted as suitable by the model were not represented within the studied material.The feasibility of using mixtures of excipients in the multivariate approach to tablet formulation to solve this problem has been investigated in the present study. By mixing different excipients of the same excipient class, it should be possible to obtain mixtures with the predicted PP's, which in turn should give a formulation with the desired properties. In order to investigate the utility of this approach, separate mixture designs were applied to both binders and fillers (diluents).As reported here, the Partial Least Squares Projections to Latent Structures (PLS) model developed in the previously published screening study has been validated in the sense that the interesting region of the PP space identified in it has been shown to contain excipients, pure or mixed, that give the formulation suitable properties. Formulations with suitable properties were found with the mixture experiments. The local models also offer several alternatives for the composition of the formulation that yield the desired disintegration time.
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| 9. |
- Gabrielsson, Jon, et al.
(författare)
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Multivariate Methods in the Development of a New Tablet Formulation
- 2003
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Ingår i: Drug Development and Industrial Pharmacy. - New York : Marcel Dekker. - 0363-9045 .- 1520-5762. ; 29:10, s. 1053-1075
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Tidskriftsartikel (refereegranskat)abstract
- The overall objective of this article is to use an efficient approach to find a suitable tablet formulation for direct compression. By using traditional approaches to statistical experimental design in tablet formulation, the number of experiments quickly grows when many descriptive variables or many excipients are included. To facilitate the screening process, a multivariate design, which allows a systematical evaluation of a large number of excipients with a limited number of experiments, was implemented. Formulations with acceptable values for disintegration time and crushing strength were obtained with some of the formulations in the present study. The multivariate experimental design strategy yielded PLS models that will be used to identify a region of interest for the optimization. The strategy is general and can be applied in many different areas of pharmaceutical research and development.
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| 10. |
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