| 82351. |
- Kolbe, Marlen, et al.
(författare)
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Impact of Thermohaline Variability on Sea Level Changes in the Southern Ocean
- 2021
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Ingår i: Journal of Geophysical Research - Oceans. - 0148-0227 .- 2156-2202. ; 126:9
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Tidskriftsartikel (refereegranskat)abstract
- The Southern Ocean is responsible for the majority of the global oceanic heat uptake that contributes to global sea level rise. At the same time, ocean temperatures do not change at the same rate in all regions and sea level variability is also affected by changes in salinity. This study investigates 10 years of steric height variability (2008–2017) in the Southern Ocean (30°S to 70°S) by analyzing temperature and salinity variations obtained from the GLORYS-031 model provided by the European Copernicus Marine Environment Monitoring Service. The thermohaline variability is decomposed into thermohaline modes using a functional Principal Component Analysis. Thermohaline modes provide a natural basis to decompose the joint temperature-salinity vertical profiles into a sum of vertical modes weighted by their respective principal components that can be related to steric height. Interannual steric height trends are found to differ significantly between subtropical and subpolar regions, simultaneously with a shift from a thermohaline stratification dominated by the first “thermal” mode in the north to the second ’saline’ mode in the South. The Polar Front appears as a natural boundary between the two regions, where steric height variations are minimized. Despite higher melt rates and atmospheric temperatures, steric height in Antarctic waters (0–2,000m) has dropped since 2008 due to higher salt content in the surface and upper intermediate layer and partially colder waters, while subtropical waters farther north have mostly risen due to increased heat storage.
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| 82352. |
- Kolbeinsson, Ari, et al.
(författare)
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To What Extent is Gamification an Effective Tool for Onboarding Users into a DHM Tool
- 2021
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Ingår i: Design, User Experience, and Usability: UX Research and Design. - Cham : Springer. - 9783030782207 - 9783030782214 ; , s. 48-66
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Konferensbidrag (refereegranskat)abstract
- Applying game-like elements to tasks or computer systems meant for serious, non-game, activities is becoming more common, and is seen as a way to support users in learning a system or to support users in performing tasks better. Applying game-like elements requires an understanding of users, the target task, and what can motivate the target users in their tasks. As in any system development, the success of the design requires validating, and this may be done multiple times in the development cycle. Some concepts, such as usability or user experience have well-established testing methods, while gamification is still a relatively immature field and evaluation methods are still being developed. This paper follows the first evaluation of a gamification system to aid with onboarding new users into the IPS IMMA digital human modelling system, offering details on the heuristic evaluation method. So early in the process, it is inevitable that problems were found, largely to do with how the motivation of users was handled, and multiple suggestions for improvements are offered.
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| 82353. |
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| 82354. |
- Kolettis, Theofilos M, et al.
(författare)
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Dose-dependent effects of sildenafil on post-ischaemic left ventricular function in the rat isolated heart.
- 2010
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Ingår i: The Journal of pharmacy and pharmacology. - : Oxford University Press (OUP). - 0022-3573 .- 2042-7158. ; 62:3, s. 346-51
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Sildenafil may be beneficial during myocardial ischaemia/reperfusion, but this effect may be dose-dependent, accounting for previous conflicting results. We have explored the effects of two acute and one chronic administration regimen on left ventricular function. METHODS: The study was conducted on 36 Wistar rats (290 +/- 7 g). Sildenafil was administered 30 min before ischaemia at a low (0.7 mg/kg, n= 8) or high (1.4 mg/kg, n= 8)dosage. The chronic treatment arm (n= 8) consisted of two daily injections of sildenafil (0.7 mg/kg) for three weeks. The control group was formed by 12 rats. Ischaemic contracture, post-ischaemic recovery and hypercontracture were measured in isolated, Langendorff-perfused preparations. KEY FINDINGS: Ischaemic contracture tended to be lower after high-dose sildenafil, while remaining unchanged after low-dose or chronic sildenafil administration. Compared with controls (62.9 +/- 2.0% of baseline developed pressure), post-ischaemic recovery was higher (P= 0.0069) after low dose (75.1 +/- 2.4%), unchanged (P= 0.13) after high dose (69.1 +/- 2.1%), but lower (P < 0.001) after chronic (42.9 +/- 4.5%) sildenafil administration. Compared with controls (71.8 +/- 3.9 mmHg), hypercontracture was higher (P= 0.0052) after chronic sildenafil administration (89.5 +/- 4.1 mmHg), but similar after acute low dose (65.7 +/- 3.3 mmHg, P= 0.33) or high dose (67.1 +/- 4.7 mmHg, P= 0.43). CONCLUSIONS: The effects of sildenafil after ischaemia/reperfusion were strongly dose-dependent. Beneficial actions on left ventricular function were evident after acute pretreatment with a low dosage, but were lost after doubling the dose. Chronic sildenafil administration deteriorated left ventricular function during ischaemia and reperfusion.
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| 82355. |
- Koliev, Faradj, et al.
(författare)
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Visiting the hegemon: Explaining diplomatic visits to the United States
- 2021
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Ingår i: Research & Politics. - : SAGE Publications. - 2053-1680 .- 2053-1680. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Diplomacy is a chief instrument of foreign policy. Through high-level diplomatic visits, governments can facilitate cooperation and signal the quality of their relations with other states. Because host countries cannot receive an indefinite number of visits, they must make strategic decisions, prioritizing some countries over others. This reveals information about their foreign policy priorities as well as diplomatic hierarchies and practices in the system as a whole. But what determines high-level diplomatic visits? Existing scholarship disagrees. In this research note, we assess the determinants of high-level diplomatic visits to the U.S. Theoretically, we draw on previous studies and formulate structural, domestic, and practice-oriented accounts of high-level visits as tools of foreign policy. Empirically, we gather original data on diplomatic visits to the U.S. by foreign leaders from 1946 to 2012. Our main results are two-fold. First, high-level diplomatic visits to the U.S. are primarily determined by structural factors such as economic relations. Second, we find clear differences in invited country profiles during and after the Cold War, demonstrating that high-level visits are used strategically to promote shifting foreign policy priorities.
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| 82356. |
- Koliwad, S. K., et al.
(författare)
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Angiopoietin-like 4 (ANGPTL4, fasting-induced adipose factor) is a direct glucocorticoid receptor target and participates in glucocorticoid-regulated triglyceride metabolism
- 2009
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Ingår i: J Biol Chem. - 1083-351X .- 1083-351X. ; 284:38, s. 25593-601
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Tidskriftsartikel (refereegranskat)abstract
- Glucocorticoids are important regulators of lipid homeostasis, and chronically elevated glucocorticoid levels induce hypertriglyceridemia, hepatic steatosis, and visceral obesity. The occupied glucocorticoid receptor (GR) is a transcription factor. However, those genes regulating lipid metabolism under GR control are not fully known. Angiopoietin-like 4 (ANGPTL4, fasting-induced adipose factor), a protein inhibitor of lipoprotein lipase, is synthesized and secreted during fasting, when circulating glucocorticoid levels are physiologically increased. We therefore tested whether the ANGPTL4 gene (Angptl4) is transcriptionally controlled by GR. We show that treatment with the synthetic glucocorticoid dexamethasone increased Angptl4 mRNA levels in primary hepatocytes and adipocytes (2-3-fold) and in the livers and white adipose tissue of mice (approximately 4-fold). We tested the mechanism of this increase in H4IIE hepatoma cells and found that dexamethasone treatment increased the transcriptional rate of Angptl4. Using bioinformatics and chromatin immunoprecipitation, we identified a GR binding site within the rat Angptl4 sequence. A reporter plasmid containing this site was markedly activated by dexamethasone, indicative of a functional glucocorticoid response element. Dexamethasone treatment also increased histone H4 acetylation and DNase I accessibility in genomic regions near this site, further supporting that it is a glucocorticoid response element. Glucocorticoids promote the flux of triglycerides from white adipose tissue to liver. We found that mice lacking ANGPTL4 (Angptl4(-/-)) had reductions in dexamethasone-induced hypertriglyceridemia and hepatic steatosis, suggesting that ANGPTL4 is required for this flux. Overall, we establish that ANGPTL4 is a direct GR target that participates in glucocorticoid-regulated triglyceride metabolism.
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| 82357. |
- Kõljalg, Urmas, et al.
(författare)
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A price tag on species
- 2022
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Ingår i: Research Ideas and Outcomes_RIO. - : Pensoft Publishers. - 2367-7163. ; 8, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Species have intrinsic value but also partake in a long range of ecosystem services of major economic value to humans. These values have proved hard to quantify precisely, making it all too easy to dismiss them altogether. We outline the concept of the species stock market (SSM), a system to provide a unified basis for valuation of all living species. The SSM amalgamates digitized information from natural history collections, occurrence data, and molecular sequence databases to quantify our knowledge of each species from scientific, societal, and economic points of view. The conceptual trading system will necessarily be very unlike that of the regular stock market, but the looming biodiversity crisis implores us to finally put an open and transparent price tag on symbiosis, deforestation, and pollution
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| 82358. |
- Kõljalg, Urmas, et al.
(författare)
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Digital identifiers for fungal species
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 352:6290, s. 1182-1183
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Tidskriftsartikel (refereegranskat)
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| 82359. |
- Kõljalg, U., et al.
(författare)
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The taxon hypothesis paradigm—On the unambiguous detection and communication of taxa
- 2020
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Ingår i: Microorganisms. - : MDPI AG. - 2076-2607. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Here, we describe the taxon hypothesis (TH) paradigm, which covers the construction, identification, and communication of taxa as datasets. Defining taxa as datasets of individuals and their traits will make taxon identification and most importantly communication of taxa precise and reproducible. This will allow datasets with standardized and atomized traits to be used digitally in identification pipelines and communicated through persistent identifiers. Such datasets are particularly useful in the context of formally undescribed or even physically undiscovered species if data such as sequences from samples of environmental DNA (eDNA) are available. Implementing the TH paradigm will to some extent remove the impediment to hastily discover and formally describe all extant species in that the TH paradigm allows discovery and communication of new species and other taxa also in the absence of formal descriptions. The TH datasets can be connected to a taxonomic backbone providing access to the vast information associated with the tree of life. In parallel to the description of the TH paradigm, we demonstrate how it is implemented in the UNITE digital taxon communication system. UNITE TH datasets include rich data on individuals and their rDNA ITS sequences. These datasets are equipped with digital object identifiers (DOI) that serve to fix their identity in our communication. All datasets are also connected to a GBIF taxonomic backbone. Researchers processing their eDNA samples using UNITE datasets will, thus, be able to publish their findings as taxon occurrences in the GBIF data portal. UNITE species hypothesis (species level THs) datasets are increasingly utilized in taxon identification pipelines and even formally undescribed species can be identified and communicated by using UNITE. The TH paradigm seeks to achieve unambiguous, unique, and traceable communication of taxa and their properties at any level of the tree of life. It offers a rapid way to discover and communicate undescribed species in identification pipelines and data portals before they are lost to the sixth mass extinction. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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| 82360. |
- Kõljalg, Urmas, et al.
(författare)
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Towards a unified paradigm for sequence-based identification of fungi.
- 2013
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Ingår i: Molecular ecology. - : Wiley. - 1365-294X .- 0962-1083. ; 22:21, s. 5271-7
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term 'species hypothesis' (SH) for the taxa discovered in clustering on different similarity thresholds (97-99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.
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