| 1. |
- Andersson, K, et al.
(författare)
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Colloidal rare earth elements in a boreal river: Changing sources and distributions during the spring flood
- 2006
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Ingår i: Geochimica Et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 70:13, s. 3261-3274
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Tidskriftsartikel (refereegranskat)abstract
- Variations in the physico-chemical speciation of the rare earth elements (REE) have been investigated in a subarctic boreal river during an intense spring flood event using prefiltered (< 100 mu m) samples, cross-flow (ultra)filtration (CFF), flow field-flow fractionation (FIFFF), and diffusive gradients in thin films (DGT). This combination of techniques has provided new information regarding the release and transport of the REE in river water. The colloidal material can be described in terms of two fractions dominated by carbon and iron, respectively. These two fractions, termed colloidal carrier phases, showed significant temporal changes in concentration and size distribution. Before the spring flood, colloidal carbon concentrations were low, the colloids being dominated by relatively large iron colloids. Colloidal concentrations increased sharply during the spring flood, with smaller carbon colloids dominating. Following the spring flood, colloidal concentrations decreased again, smaller carbon colloids still dominating. The REE are transported mainly in the particulate and colloidal phases. Before the spring flood, the REE composition of all measured fractions was similar to local till. During the spring flood, the REE concentrations in the colloidal and particulate fractions increased. The increase was most marked for the lighter REE, which therefore showed a strong enrichment when normalized to local till. Following the spring flood, the REE concentrations decreased again and reverted to a distribution similar to local till. These changes in the concentration and distributions of carbon iron and REE are interpreted in terms of changing hydrological flow paths in soil and bedrock which occur during the spring flood. (c) 2006 Elsevier Inc. All rights reserved.
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| 2. |
- Berglund, Anders, 1974-, et al.
(författare)
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THE PEDAGOGICAL DEVELOPERS INITIATIVE : SYSTEMATIC SHIFTS, SERENDIPITIES, AND SETBACKS
- 2017
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Ingår i: 13th International CDIO Conference in Calgary, Canada, June 18-22, 2017.
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Konferensbidrag (refereegranskat)abstract
- Pedagogical projects have often, at KTH Royal Institute of Technology, as well as elsewhere, been initiated and managed by individual enthusiasts rather than dedicated teams. This generally decreases the possibility of successful implementation of more ambitious ideas, e.g., changing educational programs, implementing the CDIO syllabus, or strengthening the pedagogical development of larger parts of the faculty. To enable wider and more effective change, KTH top management therefore launched a universityencompassing three-year project in 2014, in which a group of highly motivated teachers from all schools at KTH were appointed part-time pedagogical developers (PDs). The PDs were given the task of promoting pedagogical development and facilitate cooperation and knowledge exchange among faculty members, as described in two previous papers at CDIO conferences. From 2017, the outcomes of this project are supposed to be integrated parts of the KTH line organization. The project has led to numerous actions, which would have been difficult to set in motion unless given the freedom in time to explore and to develop into a collective effort rather than a myriad of individual “stand-alone” examples. By addressing key areas for pedagogical development, our group of dedicated faculty have tried to surpass the suboptimal "lock-in" of strict individual reasoning and to deal with surfaced questions and relevant issues in a broader collective manner. A major insight confirmed by the project and its many sub-projects has indeed been the fundamental importance of collegial discussions and the creation of processes that facilitate and support teacher cooperation. We have also, through discussions with faculty at KTH, confirmed the need for clearly defined, tangible incentives for teachers, motivating them to participate in pedagogical development activities, even if this means less time left for the traditional pathway to rewards within academia, i.e. research. In this paper, we chart changes that have occurred in the educational practices at KTH by describing and discussing the project’s focus on pedagogical development of faculty, actual execution of changes in the engineering educations, lessons learned along the way, and visions yet to be realised.
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| 3. |
- Bringert, Björn, 1979, et al.
(författare)
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Student Paper: HaskellDB Improved
- 2004
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Ingår i: Haskell '04: Proceedings of the ACM SIGPLAN workshop on Haskell. - 1581138504 ; , s. 108-115
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Konferensbidrag (refereegranskat)abstract
- We present an improved version of the HaskellDB database library. The original version relied on TRex, a Haskell extension supported only by the Hugs interpreter. We have replaced the use of TRex by a record implementation which uses more commonly implemented Haskell extensions. Additionally, HaskellDB now supports two different cross-platform database backends. Other changes include database creation functionality, bounded string support, performance enhancements, fixes to the optimisation logic, transaction support and more fine grained expression types.
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| 4. |
- Dahlqvist, Ralf, et al.
(författare)
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Temporal variations of colloidal carrier phases and associated trace elements in a boreal river
- 2007
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 71:22, s. 5339-5354
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Tidskriftsartikel (refereegranskat)abstract
- Elemental size distributions, from truly dissolved through colloidal to particulate, have been studied in a subarctic boreal river. The measurements, carried out during 2002, ranged from winter to summer conditions, including an intense spring flood event. Results are reported for a total of 42 elements. Size distributions were characterised using a combination of cross-flow (ultra)filtration (CFF), flow field-flow fractionation (FIFFF), and diffusive gradients in thin-films (DGT). The three techniques showed similar trends, but quantitative comparisons reveal some important differences that warrant further investigation. Previous work has identified two colloidal carrier phases in fresh waters, dominated by iron and carbon, respectively. The majority of the elements studied are associated with one or both of these colloidal carrier phases. The exceptions are the alkali metals and several anions that are only very weakly associated with colloidal material, and which therefore occur mainly as truly dissolved material (< 1 kDa in molecular weight). We discuss the likely origin for the two colloidal carrier phases and consider how associated trace elements fit into the geochemical framework. The relative affinities of the elements for iron and carbon colloidal carrier phases are related to their chemistries, and are compared with earlier data from the Delsjo Creek in southern Sweden. Elemental colloidal concentrations show strong seasonal variations related to changes in the colloidal carrier phase(s) with which they associate. In particular, many elements show a strong spring maximum in colloidal concentrations associated with the strong maximum in colloidal carbon concentration during the spring flood.
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| 5. |
- Abdelzaher, T., et al.
(författare)
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The aperiodic multiprocessor utilization bound for liquid tasks
- 2002
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Ingår i: 8th IEEE Real-Time and Embedded Technology and Applications Symposium, 2002. Proceedings. - 1545-3421. - 0769517390 ; , s. 173-184
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Konferensbidrag (refereegranskat)abstract
- Real-time scheduling theory has developed powerful tools for translating conditions on aggregate system utilization into per-task schedulability guarantees. The main breakthrough has been Liu and Layland's utilization bound for schedulability of periodic tasks. In 2001 this bound was generalized by Abdelzaher and Lu to the aperiodic task case. In this paper we further generalize the aperiodic bound to the case of multiprocessors, and present key new insights into schedulability, analysis of aperiodic tasks. We consider a special task model, called the liquid task model, representative of high-performance servers with aperiodic workloads, such as network routers, web servers, proxies, and real-time databases. For this model, we derive the optimal multiprocessor utilization bound, defined on a utilization-like metric we call "synthetic utilization". This bound allows developing constant-time admission control tests that provide utilization-based absolute delay, tees. We show that the real utilization of admitted tasks can be close to unity even when synthetic utilization is kept below the bound. Thus, our results lead to multiprocessor systems which combine constant-time admission control with high utilization while making no periodicity assumptions regarding the task arrival pattern.
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| 6. |
- Andersson-Assarsson, Johanna C., 1974, et al.
(författare)
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Evolution of age-related mutation-driven clonal haematopoiesis over 20 years is associated with metabolic dysfunction in obesity
- 2023
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Ingår i: Ebiomedicine. - 2352-3964. ; 92
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Tidskriftsartikel (refereegranskat)abstract
- Background Haematopoietic clones caused by somatic mutations with >= 2% variant allele frequency (VAF) increase with age and are linked to risk of haematological malignancies and cardiovascular disease. Recent observations suggest that smaller clones (VAF<2%) are also associated with adverse outcomes. Our aims were to determine the prevalence of clonal haematopoiesis driven by clones of variable sizes in individuals with obesity treated by usual care or bariatric surgery (a treatment that improves metabolic status), and to examine the expansion of clones in relation to age and metabolic dysregulation over up to 20 years.Methods Clonal haematopoiesis-driver mutations (CHDMs) were identified in blood samples from participants of the Swedish Obese Subjects intervention study. Using an ultrasensitive assay, we analysed single-timepoint samples from 1050 individuals treated by usual care and 841 individuals who had undergone bariatric surgery, and multiple-timepoint samples taken over 20 years from a subset (n = 40) of the individuals treated by usual care.Findings In this explorative study, prevalence of CHDMs was similar in the single-timepoint usual care and bariatric surgery groups (20.6% and 22.5%, respectively, P = 0.330), with VAF ranging from 0.01% to 31.15%. Clone sizes increased with age in individuals with obesity, but not in those who underwent bariatric surgery. In the multiple-timepoint analysis, VAF increased by on average 7% (range -4% to 24%) per year and rate of clone growth was negatively associated with HDL-cholesterol (R = -0.68, 1.74 E-04).Interpretation Low HDL-C was associated with growth of haematopoietic clones in individuals with obesity treated by usual care.
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| 7. |
- Andersson, Björn, 1974, et al.
(författare)
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Fixed-Priority Preemptive Multiprocessor Scheduling: To Partition or not to Partition
- 2000
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Ingår i: Proceedings of the IEEE Conference on Real-Time Computing Systems and Applications, December 12−14, 2000, Cheju Island, South Korea. - 1530-1427. - 0769509304 ; , s. 337−346-
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Konferensbidrag (refereegranskat)abstract
- Traditional multiprocessor real-time scheduling partitions a task set and applies uniprocessor scheduling on each processor. For architectures where the penalty of migration is low, such as uniform-memory access shared-memory multiprocessors, the non-partitioned method becomes a viable alternative. By allowing a task to resume on another processor than the task was preempted on, some task sets can be scheduled where the partitioned method fails.We address fixed-priority scheduling of periodically arriving tasks on $m$ equally powerful processors having a non-partitioned ready queue. We propose a new priority-assignment scheme for the non-partitioned method. Using an extensive simulation study, we show that the priority-assignment scheme has equivalent performance to the best existing partitioning algorithms, and outperforms existing fixed-priority assignment schemes for the non-partitioned method. We also propose a dispatcher for the non-partitioned method which reduces the number of preemptions to levels below the best partitioning schemes.
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| 8. |
- Andersson, Björn, 1974, et al.
(författare)
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Global Priority-Driven Aperiodic Scheduling on Multiprocessors
- 2003
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Ingår i: Proceedings. International Parallel and Distributed Processing Symposium, 2003. - 1530-2075. - 0769519261
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Konferensbidrag (refereegranskat)abstract
- This paper studies multiprocessor scheduling for aperiodic tasks where future arrivals are unknown. A previously proposed priority-driven scheduling algorithm for periodic tasks with migration capability is extended to aperiodic scheduling and is shown to have a capacity bound of 0.5. This bound is close to the best achievable for a priority-driven scheduling algorithm. With an infinite number of processors, no priority-driven scheduling algorithm can perform better. We also propose a simple admission controller which guarantees that admitted tasks meet their deadlines and for many workloads, it admits tasks so that the utilization can be kept above the capacity bound.
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| 9. |
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| 10. |
- Andersson, Björn, 1974, et al.
(författare)
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Partitioned Aperiodic Scheduling on Multiprocessors
- 2003
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Ingår i: Proceedings. International Parallel and Distributed Processing Symposium, 2003. - 1530-2075. - 0769519261
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Konferensbidrag (refereegranskat)abstract
- This paper studies multiprocessor scheduling for aperiodic tasks where future arrivals are unknown. We propose an algorithm for tasks without migration capabilities and prove that it has a capacity bound of 0.31. No algorithm for tasks without migration capabilities can have a capacity bound greater than 0.50.
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