| 1. |
- Barbary, K., et al.
(författare)
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THE HUBBLE SPACE TELESCOPE CLUSTER SUPERNOVA SURVEY. II. THE TYPE Ia SUPERNOVA RATE IN HIGH-REDSHIFT GALAXY CLUSTERS
- 2012
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 745:1, s. 32-
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Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 < z < 1.46 from the Hubble Space Telescope Cluster Supernova Survey. This is the first cluster SN Ia rate measurement with detected z > 0.9 SNe. Finding 8 +/- 1 cluster SNe Ia, we determine an SN Ia rate of 0.50(-0.19)(+0.23) (stat) (+0.10)(-0.09) (sys) h(70)(2) SNuB (SNuB equivalent to 10(-12) SNe (L-1)circle dot(,B) yr(-1)). In units of stellar mass, this translates to 0.36(-0.13)(+0.16) (stat) (+0.07)(-0.06) (sys) h(70)(2) SNuM (SNuM = 10(-12) SNe M-1 circle dot yr(-1)). This represents a factor of approximate to 5 +/- 2 increase over measurements of the cluster rate at z < 0.2. We parameterize the late-time SN Ia delay time distribution (DTD) with a power law: Psi(t) t(s). Under the approximation of a single-burst cluster formation redshift of z(f) = 3, our rate measurement in combination with lower-redshift cluster SN Ia rates constrains s = -1.41(-0.40)(+0.47), consistent with measurements of the DTD in the field. This measurement is generally consistent with expectations for the double degenerate scenario and inconsistent with some models for the single degenerate scenario predicting a steeper DTD at large delay times. We check for environmental dependence and the influence of younger stellar populations by calculating the rate specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, finding results similar to the full cluster rate. Finally, the upper limit of one hostless cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts.
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| 2. |
- Havton, LA, et al.
(författare)
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Systemic administration of cholera toxin B subunit conjugated to horseradish peroxidase in the adult rat labels preganglionic autonomic neurons, motoneurons, and select primary afferents for light and electron microscopic studies
- 2005
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Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 1872-678X .- 0165-0270. ; 149:2, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- Retrograde and transganglionic labeling techniques are commonly used to visualize subsets of neurons and sensory afferent projections in the nervous system. These methods commonly require anesthesia and surgical methods. However, some tracers can also be administered systemically in awake animals, thus reducing risks associated with anesthesia and surgery and allowing for labeling of neuronal populations that are difficult to label with local tracer injections. Here, we demonstrate in the adult rat that intraperitoneal administration of cholera toxin subunit B conjugated to horseradish peroxidase labels preganglionic autonomic neurons, motoneurons, and the terminal projections of select primary afferents for both light and electron microscopic studies. We demonstrate also that this method can be combined with post-embedding immunogold labeling to detect amino acid transmitters in synaptic boutons.
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| 3. |
- Vonk, Jorien, et al.
(författare)
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A centennial record of fluvial organic matter input from the discontinuous permafrost catchment of Lake Torneträsk
- 2012
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Ingår i: Journal of Geophysical Research. - : American Geophysical Union (AGU). - 0148-0227 .- 2156-2202. ; 117:G03018, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- High-latitude regions are underlain by the most organic carbon (OC)-rich soils on earth and currently subject to intense climate warming, potentially increasing remobilization and mineralization of soil OC. Sub-Arctic Scandinavia is located on the 0°C mean annual isotherm and is therefore particularly vulnerable to climate change. This study aimed to establish a baseline for soil OC release over the past century into Lake Torneträsk, the largest lake in sub-Arctic Scandinavia, through bulk geochemical and molecular radiocarbon analyses in chronologically constrained sediment cores. Our results suggest a dominance of peat-derived terrestrial OC inflow. We show that the annual terrestrial OC inflow to the lake is ∼12 times higher than the in-lake produced particulate OC, and consists for a large part (ca. 60%) of old OC from deep reservoirs in the catchment. The sedimentary record shows signs of increasing inflow of more degraded terrestrial matter since ∼1975, as indicated by increasing %TOC concentrations, a lower δ13C value and lower TOC:TN ratios. Based on simultaneous changes in local climate and reported signs of permafrost degradation (e.g., active layer deepening, mire/peat erosion), the observed changes in the sedimentary record of Scandinavia's largest mountain lake likely reflect a climate warming-induced change in terrestrial OC inflow.
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| 4. |
- Lillo Cea, Pablo Antonio, 1989-
(författare)
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The World-Class Ordination : A Field Theory Approach to the Study of Global University Rankings
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Using Pierre Bourdieu’s field theory, this thesis explores the idea of a “world-class university” by analysing the narratives and dynamics that shape this classification in the context of global university rankings. It uses a combination of methods, including historical studies, bibliometrics, multiple correspondence analysis, and social network analysis to examine the socio-historical factors determining world-class status in higher education.The research reinterprets the rise and evolution of global university rankings, framing it as a process of field formation. Influential entities like the IREG Observatory and the Center for World-Class Universities have been instrumental in fostering a global discourse that encourages competition among higher education institutions, leading to the establishment of a worldwide system for evaluating academic excellence.A comparative analysis of institutions, nations, and regions based on ranking results over two decades spotlights the enduring dominance of U.S. and U.K. institutions amidst the rising presence of Chinese. Focusing on 2022 data from the Academic Ranking of World Universities, QS World University Ranking, and Times Higher Education World University Ranking using Multiple Correspondence Analysis. It finds that prestige, heavily influenced by private reputation surveys, outweighs performance or internationalisation metrics in these rankings. The analysis also reveals a contrast between international recruitment and a domestic orientation, with English-speaking institutions attracting more international students and faculty. A dichotomy in scientific recognition emerges, opposing older institutions with award-winning alumni and staff to younger universities excelling in citations per faculty. Euclidean clustering supports these findings, identifying distinct groups of institutions, such as domestically focused Asian institutions and well-rounded Anglo-Saxon universities.Lastly, the thesis examines patterns of academic collaboration using social network analysis, with a focus on Swedish, English, and German higher education institutions. It observes a shift in partnerships from American to Asian counterparts, indicating Asia’s ascending role in the global academic landscape and reflecting changes in global university rankings. Overall, this study enhances our comprehension of higher education from a global perspective, uncovering the pervasive dominance of the Anglo-Saxon educational model in university evaluations, where the quantification of reputation is misrecognised as academic excellence.
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| 7. |
- Fornäs, Johan, 1952-
(författare)
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Symbols and narratives of Europe : Three tropes
- 2020
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Ingår i: Punctum: International journal of semiotics. - : Aristotle University of Thessaloniki. - 2459-2943. ; 6:2, s. 85-100
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Tidskriftsartikel (refereegranskat)abstract
- Throughout history, attempts have been made to identify Europe as a geographical, political, social, and cultural entity. Recent efforts to establish key symbols and narratives of Europe have focused on a set of central signifying elements, even if there is a wide and contradictory range of ways to define, structure, and interpret them. An introductory remark on the current debate on the need for renewed European self-reflection paves the way for some conceptual clarifications of my approach to concepts like culture, meaning, identity and mediation. A methodological reflection accompanies this on how to use semiotic tools in cultural studies based on critical hermeneutics. The concept of culture used here is based on the signifying practice of mediating meaning-making, linking imagination to communication in a triangular dynamic between texts, subjects, and contexts. Examples are given from two research projects on a broad and diverse range of European symbols and narratives, illustrating such interpretive research results. European identifications are crystallized and spun around three dominant tropes: supreme universality, resurrection from division, and communicative mobility. Their intricate tensions and interrelations attest to how deeply Europe remains a highly contested and dynamic meaning cluster.
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| 8. |
- Wang, Di -Si, et al.
(författare)
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Finite element analysis of the main reactor vessel in the China Initiative Accelerator Driven System
- 2023
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Ingår i: Engineering Failure Analysis. - : Elsevier BV. - 1350-6307 .- 1873-1961. ; 146
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Tidskriftsartikel (refereegranskat)abstract
- The China Initiative Accelerator Driven System (CiADS) was proposed by China Academy of Science since 2015. The reactor in CiADS is a subcritical fast neutron reactor cooled by a liquid lead-bismuth eutectic. The reactor operates at high temperature and bears high thermal stress. In addition to the heavy weight of the whole reactor, the vessel will bear large effective stress. If the effective stress exceeds the limit of the material, defects and cracks may occur on the main reactor vessel, which will affect the safety performances of the reactor. Therefore, it is very important to analyze the effective stress field of the reactor vessel. In this paper, the finite element analysis software ADINA was applied to analyze the reactor vessel in CiADS. We can preliminarily prove that the maximum effective stress that the vessel will bear during the postulated Unprotected Loss of Flow (ULOF) and Unprotected Transient over Power (UTOP) accidents is less than the yield strength of 316L stainless steel. Therefore, we can preliminarily conclude that the current ma-terial selection and structural design of the CiADS vessel could survive the postulated transient accidents considering the effective stress effect.
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