| 1. |
- In ’t Veld, Sjors G.J.G., et al.
(författare)
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Detection and localization of early- and late-stage cancers using platelet RNA
- 2022
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Ingår i: Cancer Cell. - : Elsevier. - 1535-6108 .- 1878-3686. ; 40:9, s. 999-1009.e6
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Tidskriftsartikel (refereegranskat)abstract
- Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I–IV cancer patients and in half of 352 stage I–III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening.
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| 2. |
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| 3. |
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| 4. |
- Campmans-Kuijpers, M.J.E., et al.
(författare)
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Isocaloric substitution of carbohydrates with protein: The association with weight change and mortality among patients with type 2 diabetes
- 2015
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Ingår i: Cardiovascular Diabetology. - : Springer Science and Business Media LLC. - 1475-2840. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- © 2015 Campmans-Kuijpers et al.; licensee BioMed Central. Background: The health impact of dietary replacement of carbohydrates with protein for patients with type 2 diabetes is still debated. This study aimed to investigate the association between dietary substitution of carbohydrates with (animal and plant) protein and 5-year weight change, and all-cause and cardiovascular (CVD) mortality risk in patients with type 2 diabetes. Methods: The study included 6,107 diabetes patients from 15 European cohorts. Patients with type 1 diabetes were excluded. At recruitment, validated country-specific food-frequency questionnaires were used to estimate dietary intake. Multivariable adjusted linear regression was used to examine the associations between dietary carbohydrate substitution with protein and 5-year weight change, and Cox regression to estimate hazard ratios (HRs) for (CVD) mortality. Results: Annual weight loss of patients with type 2 diabetes was 0.17 (SD 1.24) kg. After a mean follow-up of 9.2 (SD 2.3)y, 787 (13%) participants had died, of which 266 (4%) deaths were due to CVD. Substitution of 10 gram dietary carbohydrate with total (ß = 187 [75;299]g) and animal (ß = 196 [137;254]g) protein was associated with mean 5-year weight gain. Substitution for plant protein was not significantly associated with weight change (β = 82 [-421;584]g). Substitution with plant protein was associated with lower all-cause mortality risk (HR = 0.79 [0.64;0.97]), whereas substitution with total or animal protein was not associated with (CVD) mortality risk. Conclusions: In diabetes patients, substitution with plant protein was beneficial with respect to weight change and all-cause mortality as opposed to substitution with animal protein. Therefore, future research is needed whether dietary guidelines should not actively promote substitution of carbohydrates by total protein, but rather focus on substitution of carbohydrates with plant protein.
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| 5. |
- van Erp, Susan, et al.
(författare)
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Lrig2 Negatively Regulates Ectodomain Shedding of Axon Guidance Receptors by ADAM Proteases
- 2015
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Ingår i: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 35:5, s. 537-552
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Tidskriftsartikel (refereegranskat)abstract
- Many guidance receptors are proteolytically cleaved by membrane-associated metalloproteases of the ADAM family, leading to the shedding of their ectodomains. Ectodomain shedding is crucial for receptor signaling and function, but how this process is controlled in neurons remains poorly understood. Here, we show that the transmembrane protein Lrig2 negatively regulates ADAM-mediated guidance receptor proteolysis in neurons. Lrig2 binds Neogenin, a receptor for repulsive guidance molecules (RGMs), and prevents premature Neogenin shedding by ADAM17 (TACE). RGMa reduces Lrig2-Neogenin interactions, providing ADAM17 access to Neogenin and allowing this protease to induce ectodomain shedding. Regulation of ADAM17-mediated Neogenin cleavage by Lrig2 is required for neurite growth inhibition by RGMa in vitro and for cortical neuron migration in vivo. Furthermore, knockdown of Lrig2 significantly improves CNS axon regeneration. Together, our data identify a unique ligand-gated mechanism to control receptor shedding by ADAMs and reveal functions for Lrigs in neuron migration and regenerative failure.
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| 10. |
- Muller-Lissner, S A, et al.
(författare)
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Interobserver agreement in defecography--an international study
- 1998
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Ingår i: Zeitschrift für Gastroenterologie. - 0044-2771. ; 36:4, s. 273-279
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Defecography is considered to be an essential investigation in the evaluation of functional anorectal disorders, but the agreement between observers from different clinical centers has never been evaluated. METHODS: 14 defecographic studies were selected aimed to cover the most relevant defecographic findings responsible for disordered defecation. Eight studies were considered unequivocal, but six were thought to be controversial. All were sent to the ten participants in Europe and the US (five proctosurgeons, three radiologists, two gastroenterologists). They evaluated the studies using a previously agreed upon questionnaire. Interobserver agreement was quantified by kappa statistics and by the proportions of positive and negative agreement as compared to chance agreement, respectively. RESULTS: Overall, only the completeness of rectal emptying and the presence of a rectocele achieved acceptable kappa values above 0.4. When restricting the evaluation to the studies considered to be unequivocal, agreement improved considerably and was moderate to good for all items describing the images (kappa 0.43-0.63). However, whether proctosurgery should be performed and whether defecography contributed to the management of the particular patient remained controversial with very low kappa. CONCLUSIONS: It is doubtful whether defecography contributes substantially to the management of patients with disordered defecation.
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| 11. |
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| 12. |
- Pearce, Christof, et al.
(författare)
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Heinrich 0 on the east Canadian margin : Source, distribution and timing
- 2015
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Ingår i: Paleoceanography. - 0883-8305 .- 1944-9186. ; 30:12, s. 1613-1624
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Tidskriftsartikel (refereegranskat)abstract
- The last deglaciation was marked by intervals of rapid climatic fluctuations accompanied by glacial advances and retreats along the eastern margin of the Laurentide Ice Sheet (LIS). One of these climatic events, the Younger Dryas cold reversal, was accompanied by a detrital carbonate event referred to as "Heinrich event 0" (H0) that deposited ice-rafted debris and especially detrital carbonate-rich (DC) sediment layers in the western and southern Labrador Sea. The precise age, duration, source, and geographical distribution of the H0 DC event, however, are not entirely clear. A high-sedimentation rate sequence cored off southern Newfoundland yielded an age of ca. 11.5 – 11.3 cal. kyr BP for this layer, thus pointing to its deposition directly following the Younger Dryas termination, likely associated with rapid ice retreat and warming at the onset of the Holocene. At the study site, the H0 layer contains increased concentrations of detrital carbonates (calcite/dolomite ratio ~ 2.5:1) and a mature biomarker composition, similar to that found in Heinrich Layers 1, 2, 4 and 5, which together suggest an origin from Hudson Strait. Grain size analysis indicates that the H0-sediments were transported to the study site mostly through shallow plumes along the Labrador Shelf, with some hyperpycnal dispersal, deeper, along the slope and rise. Our data thus point to a large meltwater release caused by retreat of the ice margin in the Hudson Strait area. The relvatively short duration of the H0 layer, and its timing right after a major climatic transition, combined with its ubiquitous regional occurence makes it valuable for correlating different sediment records from the western Labrador Sea.
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| 13. |
- Pucher, E, et al.
(författare)
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Recommendations on Specifications for Tyre and Vehicle Requirements
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report gives an overview of the general effects of various tyre and vehicle parameters, a brief review of the SILVIA database, and analyses of the influences of various tyre and vehicle parameters on traffic noise. These analyses are based on data present in the SILVIA database, supplemented with results from relevant literature. Based on these analyses recommendations have been made concerning guidelines for vehicle and tyre manufacturers and legislators as a way to improve the performance of low noise surfaces through optimising the vehicle and tyres.
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| 14. |
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| 16. |
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| 17. |
- van Schaarenburg, Rosanne A., et al.
(författare)
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Marked variability in clinical presentation and outcome of patients with C1q immunodeficiency
- 2015
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Ingår i: Journal of Autoimmunity. - : Elsevier BV. - 0896-8411 .- 1095-9157. ; 62, s. 39-44
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Globally approximately 60 cases of C1q deficiency have been described with a high prevalence of Systemic Lupus Erythematosus (SLE). So far treatment has been guided by the clinical presentation rather than the underlying C1q deficiency. Recently, it was shown that C1q production can be restored by allogeneic hematopoietic stem cell transplantation. Current literature lacks information on disease progression and quality of life of C1q deficient persons which is of major importance to guide clinicians taking care of patients with this rare disease.Methods: We performed an international survey, of clinicians treating C1q deficient patients. A high response rate of >70% of the contacted clinicians yielded information on 45 patients with C1q deficiency of which 25 are published.Results: Follow-up data of 45 patients from 31 families was obtained for a median of 11 years after diagnosis. Of these patients 36 (80%) suffer from SLE, of which 16 suffer from SLE and infections, 5 (11%) suffer from infections only and 4 (9%) have no symptoms. In total 9 (20%) of the C1q deficient individuals had died. All except for one died before the age of 20 years. Estimated survival times suggest 20% case-fatality before the age of 20, and at least 50% of patients are expected to reach their middle ages.Conclusion: Here we report the largest phenotypic data set on C1q deficiency to date, revealing high variance; with high mortality but also a subset of patients with an excellent prognosis. Management of C1q deficiency requires a personalized approach.
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| 18. |
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| 19. |
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| 20. |
- Andresen, Camilla Snowman, et al.
(författare)
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Holocene climate variability at multidecadal time scales detected by sedimentological indicators in a shelf core NW off Iceland
- 2005
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Ingår i: Marine Geology. - : Elsevier BV. - 0025-3227. ; 214:4, s. 323-338
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Tidskriftsartikel (refereegranskat)abstract
- A Holocene sediment record is presented from the Djupall trough, situated on the inner shelf northwest of Iceland. The paleoclimatic development has been interpreted on the basis of mass accumulation rate, carbonate content, mean grain size, sediment petrology and 29 radiocarbon dates. The results demonstrate in the early Holocene (10,000-8000 cal year BP) high sediment accumulation rates attributable to the effect of enhanced sediment mobilisation under influence of a relatively low sea level and remobilisation of glacial sediments on the sparsely vegetated Vestfirdir peninsula. The data suggest that a general southward displacement of the Polar Front commenced around 5000-4000 cal year BP. A new proxy for Holocene climatic variability is presented by the basalt/plagioclase ratio in the 63-100 mum fraction. High basalt/plagioclase values are primarily related to periods of increased storminess and bottom current energy, which enhanced the transport of basaltic sediment from the coastal zone towards the outer shelf. Advection of polar waters containing basalt-rich IRD from the eastern Greenland Blosseville Kyst basalt province may also have contributed to increased basalt/plagioclase ratios. The correlation between basalt/plagioclase ratios and proxies of solar activity (C-14 production and Be-10 flux) was explored and suggests that some of the centennial-scale peaks in colder climate could be related to increased nuclide production in the upper atmosphere. In addition, it was found that the Medieval Warm Period (c. 1100-700 cal year BP) was characterised by strong cyclone activity over the Iceland region. Intense atmospheric circulation during this period has been confirmed also by other studies in the northern North Atlantic region.
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| 21. |
- Bartzela, T N, et al.
(författare)
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A two-centre study on facial morphology in patients with complete bilateral cleft lip and palate at nine years of age.
- 2011
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Ingår i: International journal of oral and maxillofacial surgery. - : Elsevier BV. - 1399-0020 .- 0901-5027. ; 40:8, s. 782-9
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare craniofacial morphology and soft tissue profiles in patients with complete bilateral cleft lip and palate at 9 years of age, treated in two European cleft centres with delayed hard palate closure but different treatment protocols. The cephalometric data of 83 consecutively treated patients were compared (Gothenburg, N=44; Nijmegen, N=39). In total, 18 hard tissue and 10 soft tissue landmarks were digitized by one operator. To determine the intra-observer reliability 20 cephalograms were digitized twice with a monthly interval. Paired t-test, Pearson correlation coefficients and multiple regression models were applied for statistical analysis. Hard and soft tissue data were superimposed using the Generalized Procrustes Analysis. In Nijmegen, the maxilla was protrusive for hard and soft tissue values (P=0.001, P=0.030, respectively) and the maxillary incisors were retroclined (P<0.001), influencing the nasolabial angle, which was increased in comparison with Gothenburg (P=0.004). In conclusion, both centres showed a favourable craniofacial form at 9-10 years of age, although there were significant differences in the maxillary prominence, the incisor inclination and soft tissue cephalometric values. Follow-up of these patients until facial growth has ceased, may elucidate components for outcome improvement.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
- Lacy, Michael, et al.
(författare)
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Cell-specific and divergent roles of the CD40L-CD40 axis in atherosclerotic vascular disease
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Atherosclerosis is a major underlying cause of cardiovascular disease. Previous studies showed that inhibition of the co-stimulatory CD40 ligand (CD40L)-CD40 signaling axis profoundly attenuates atherosclerosis. As CD40L exerts multiple functions depending on the cell-cell interactions involved, we sought to investigate the function of the most relevant CD40L-expressing cell types in atherosclerosis: T cells and platelets. Atherosclerosis-prone mice with a CD40L-deficiency in CD4+ T cells display impaired Th1 polarization, as reflected by reduced interferon-γ production, and smaller atherosclerotic plaques containing fewer T-cells, smaller necrotic cores, an increased number of smooth muscle cells and thicker fibrous caps. Mice with a corresponding CD40-deficiency in CD11c+ dendritic cells phenocopy these findings, suggesting that the T cell-dendritic cell CD40L-CD40 axis is crucial in atherogenesis. Accordingly, sCD40L/sCD40 and interferon-γ concentrations in carotid plaques and plasma are positively correlated in patients with cerebrovascular disease. Platelet-specific deficiency of CD40L does not affect atherogenesis but ameliorates atherothrombosis. Our results establish divergent and cell-specific roles of CD40L-CD40 in atherosclerosis, which has implications for therapeutic strategies targeting this pathway.
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| 28. |
- Moros, M, et al.
(författare)
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Quartz content and the quartz-to-plagioclase ratio determined by X-ray diffraction: a proxy for ice rafting in the northern North Atlantic?
- 2004
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Ingår i: Earth and Planetary Science Letters. - 1385-013X. ; 218:3-4, s. 389-401
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Tidskriftsartikel (refereegranskat)abstract
- Many paleoceanographic reconstructions of the glacial North Atlantic include estimates of iceberg discharge, which are based on the variable abundance of ice-rafted detritus (IRD) in deep-sea sediments. IRD abundance is most often determined by the mechanical separation and painstaking counting of terrigenous particles larger than a specified threshold grain size, typically 150 mum. Here we present a new proxy for IRD based on X-ray diffraction (XRD) analysis of bulk sediments. This approach complements results obtained from standard techniques while offering several distinct advantages. In addition to the rapid production of objective data, XRD measurements on bulk sediments are sensitive to a broader and more characteristic grain size range than counts of individual coarse lithic fragments. The technique is demonstrated in a study of 12 sediment cores from the North Atlantic. Bulk quartz content and the quartz-to-plagioclase ratio exhibit peak-to-peak correspondence to manual counting results, which verifies the identification of large IRD influxes. The XRD data also reveal variations between the manually identified peaks, suggesting increased sensitivity to low-level, distal, or sea-ice sources of IRD. A saw-tooth pattern emerges in many IRD events, which supports a link between ice rafting and atmospheric temperature changes over Greenland, and providing further evidence of the influence of climate on iceberg discharges. (C) 2003 Elsevier B.V. All rights reserved.
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| 29. |
- Moros, M, et al.
(författare)
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Sea surface temperatures and ice rafting in the Holocene North Atlantic: climate influences on Northern Europe and Greenland
- 2004
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 23:20-22, s. 2113-2126
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Tidskriftsartikel (refereegranskat)abstract
- The oceanographic conditions in the high-latitude North Atlantic ocean during the Holocene were reconstructed through analyses of sea surface temperature (SST; alkenone unsaturation ratios) and ice rafting (mineralogy and grain size) from two sediment sequences, one recovered from the Reykjanes Ridge at 59degreesN and the other from the Norwegian Sea at 68degreesN. Comparison of our records to published ice core and terrestrial proxy-climate data sets suggests that atmospheric temperature changes over Northern Europe and Greenland were coupled to SST variability and ice rafting. The records outline four major climatic phases: (i) an early-Holocene Thermal Maximum that lasted until approximately 6.7 kyr BP, (ii) a distinctly cooler phase associated with increased ice rafting between 6.5 and 3.7 kyr BP, (iii) a transition to generally warmer, but relatively unstable climate conditions between 3.7 and 2 kyr BP and (iv) a second distinct SST decline that took place between 2 and 0.5 kyr BP. In contrast to the dominant control of Northern Hemisphere summer insolation on early-Holocene climate development (via strong seasonality), the trigger for the onset of relatively unstable climatic conditions in the North Atlantic at 3.7 kyr BP is not straightforward. However, it is possible that this change was triggered by late-Holocene winter insolation increase at high northern latitude and/or by inter-hemispheric changes in orbital forcing. The late-Holocene Neoglaciation trend, which is characteristic of numerous terrestrial archives in northern Europe, may not only be attributed to a gradual decrease in orbitally forced summer temperature, but also to increase snow precipitation at high northern latitudes during generally milder winters. (C) 2004 Elsevier Ltd. All rights reserved.
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| 30. |
- Moros, M, et al.
(författare)
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Were glacial iceberg surges in the North Atlantic triggered by climatic warming?
- 2002
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Ingår i: Marine Geology. - 0025-3227. ; 192:4, s. 393-417
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution physical, mineralogical, sedimentological and micropalaeontological studies were carried out on North Atlantic cores from the Reykjanes Ridge at 59degreesN and from the region southwest of the Faeroe Islands. All core sites are situated along the pathway of Iceland-Scotland Overflow Water (ISOW) and the various parameters measured display similar features. Previously identified carbonate oscillations [Keigwin and Jones (1994) J. Geophys. Res., 99, 12397-12410] in the time span back to the Marine Isotope Stage 5-4 transition and Late Glacial lithic events [Bond and Lotti (1995) Science, 267, 1005-1010], such as the Heinrich ice-rafting events, are all represented in the core records. Long-term trends and higher-frequency changes in ISOW intensity were reconstructed on the basis of various independent proxy records. The long-term trends in circulation match theoretical orbitally forced insolation changes. Our observed links between ice-rafted detritus (IRD) input, variations in sea surface temperature (SST) and circulation at greater depth point to the need to re-examine the origin of IRD events. We suggest that these events may have been triggered by enhanced, partly sub-surface, heat transport to the-north. Enhanced northward heat transport may have caused bottom melting of floating outlet glaciers and ice shelves, leading to increased iceberg discharge and ice sheet destabilization. This discharge. resulted in lower SST's and a lower temperature over Greenland. Thus, as shown by our records, this scenario implies a temporary de-coupling of surface processes and circulation at greater depth. A key feature is the occurrence of a-saw-tooth pattern in the marine data, which is similar to the Greenland ice core records. Moreover, the 'warming' theory of IRD events would explain the observed 'out-of-phase' relationship between the Greenland and Antarctic ice-core records and also the rapid establishment of higher temperatures over Greenland immediately after the cold phases (stadials) of the Dansgaard-Oeschger cycles.
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| 31. |
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| 32. |
- Rasmussen, Tine, et al.
(författare)
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Millennial-scale glacial variability versus Holocene stability: changes in planktic and benthic foraminifera faunas and ocean circulation in the North Atlantic during the last 60 000 years
- 2003
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Ingår i: Marine Micropaleontology. - 1872-6186. ; 47:1-2, s. 143-176
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Forskningsöversikt (refereegranskat)abstract
- Two piston cores, DS97-2P from the Reykjanes Ridge in the central North Atlantic Ocean (1685 m water depth) and ENAM33 from southwest of the Faeroe Islands in the NE Atlantic (1217 m water depth), have been investigated for their planktic and benthic foraminiferal content. DS97-2P is situated near the Subarctic Front and productivity measured by accumulation rates of benthic and planktic foraminifera has been generally high during the Holocene. The productivity shows a clear decrease from an early Holocene maximum to a late Holocene minimum. Coeval changes in the benthic faunas indicate that the food supply changed from large, irregular pulses during the early Holocene to a more sustained flux during the late Holocene. Presumably in concert with decreasing bottom current activity oxygen conditions in the bottom water became poorer. Another feature of the late Holocene is an increasing instability of the North Atlantic thermohaline circulation regime. Nevertheless, the changes in faunal composition and productivity during the Holocene were gradual as compared to the discontinuous distribution patterns and abrupt productivity shifts during the glacial. The glacial shifts were on a millennial time scale and correlate with the interstadial-stadial phases of the Dansgaard-Oeschger cycles in the Greenland ice cores. The faunas of the warm interstadial phases resembled the Holocene faunas, and both surface and bottom productivity was high. The faunas suggest that the interstadial circulation pattern was very similar to the modern system with convection in the Nordic seas and generation of North Atlantic Deep Water. The planktic faunas during the cold stadials and Heinrich events were completely dominated by the polar species Neogloboquadrina pachyderma s, and surface conditions were cold and the productivity low. The benthic faunas were dominated by species that presently thrive in areas with a low amount of food and reduced oxygen content. The water column was probably stratified with low saline, cold surface water overlying poorly aerated, intermediate water masses.
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| 33. |
- Rasmussen, Tine, et al.
(författare)
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The Faroe-Shetland Gateway: Late Quaternary water mass exchange between the Nordic seas and the northeastern Atlantic
- 2002
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Ingår i: Marine Geology. - 0025-3227. ; 188:1-2, s. 165-192
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Tidskriftsartikel (refereegranskat)abstract
- Thirteen piston and gravity cores from the Faroe-Shetland area were investigated for their planktic and benthic foraminiferal and oxygen isotopic distributions. Eight time-slices between 18 ka BP and the present were reconstructed to study variations in surface and deep water exchange between the SE Norwegian Sea and the northeast Atlantic Ocean. Today, a relatively strong northward flow of warm North Atlantic surface water is counterbalanced by a southward outflow of newly convected cold bottom water, the Norwegian Sea Overflow Water. During the last glacial maximum at 18 ka BP both the surface and bottom flows were slow and the climate conditions were Arctic. The convection north of the Faroe area was weak and unstable. The first indication of the deglaciation is a decrease in the planktic oxygen isotope values discernible southwest of the Faroe Islands at 15.5 ka BP. The deglaciation proceeded northeast and eastward synchronous with a gradual intensification of northward flowing warmer Atlantic Intermediate Water along the sea bottom. Meltwater fluxes increased between 14 and 13 ka BP producing cold surface waters, and the climatic cooling was extreme. There was no southward overflow of cold bottom water during this time period and the exchange of water masses between the Nordic seas and the North Atlantic Ocean was essentially reversed, i.e. estuarine. During the Bolling Interstadial at 12.5 ka BP northward flowing warm surface water was present to the east of the Faroe-Shetland Channel, wedged below a tongue of polar water spreading from the northwest and reaching into the Faroe-Shetland Channel. Convection in the Nordic seas and overflow of cold deep water started during the Bolling Interstadial. The polar water spread more eastward and southward during the following cold spell, the Younger Dryas, around 10.3 ka BP. The polar water was overlying the warmer, but more saline Atlantic water, which flowed northward below the cold surface water. The overflow of cold bottom water was supposedly only slightly weaker than during the Bolling Interstadial. Strong inflow of warm surface water took place during the Early Holocene at 9.5 ka BP and relatively dense cold water flowed southward along the bottom. The rate of water mass exchange reached a maximum at 6.5 ka BP, when both the inflow of warm Atlantic surface water and the outflow of cold dense bottom water appear to have been stronger than today.
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| 34. |
- Seidenkrantz, M. S., et al.
(författare)
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Southwest Greenland shelf glaciation during MIS 4 more extensive than during the Last Glacial Maximum
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Although geological and modelling evidence indicate that the last glacial inception in North America was in NE Canada, little is known about the glacial response of the nearby western Greenland Ice Sheet (GIS) during the glacial advance of marine oxygen isotope stage 4 (MIS4). Our multi-proxy study of a marine sediment core collected about 60 km southwest of the Outer Hellefisk Moraines demonstrates that in the southern Davis Strait region the most extreme Greenland shelf glaciation of the last glacial cycle occurred during MIS 4, with another prominent glacial advance at 37-33 kyr BP. During those periods the GIS likely reached the Outer Hellefisk Moraines in this area. Except for these two periods, our data suggest significant advection of relatively warm Irminger Sea Water by the West Greenland Current since MIS 4. This advection likely limited the extent of the MIS2 glaciation on the SW Greenland shelf. Decreased precipitation over southwestern Greenland predicted by atmospheric models as a downstream effect of a much larger MIS2 Laurentide Ice Sheet may have played an additional role.
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| 35. |
- Seidenkrantz, Marit-Solveig, et al.
(författare)
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Two-step deglaciation at the oxygen isotope stage 6/5e transition: the Zeifen-Kattegat climatic oscillation
- 1996
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Ingår i: Quaternary Science Reviews. - 0277-3791 .- 1873-457X. ; 15:1, s. 63-75
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Tidskriftsartikel (refereegranskat)abstract
- Comparison of marine, lacustrine, and terrestrial records from twenty-four sites suggests the existence of a 'Younger Dryas'-type climate oscillation just prior to the Oxygen Isotope Stage 6/5e boundary. These records include results from biostratigraphic, pedostratigraphic, and speleothem studies, as well as analyses of stable isotope compositions of marine records and ice cores. The climate oscillation is named after the warm Zeifen Interstadial and the cold Kattegat Stadial. The Zeifen Interstadial may be related to a major meltwater pulse in the Baffin Bay-Labrador Sea-Norwegian Sea region. The climate oscillation is presumably in part a result of a variation in ocean circulation, especially in the strength of the North Atlantic Drift, but changes in the atmospheric circulation also played an important role. The geographically widespread distribution of the oscillation suggests that the two-step deglaciation influenced both the northern and southern hemispheres.
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| 36. |
- Sheldon, C. M., et al.
(författare)
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Variable influx of West Greenland Current water into the Labrador Current through the last 7200 years : a multiproxy record from Trinity Bay (NE Newfoundland)
- 2015
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Ingår i: arktos. - : Springer Science and Business Media LLC. - 2364-9453 .- 2364-9461. ; 1:8
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Tidskriftsartikel (refereegranskat)abstract
- A multiproxy study of marine sediment gravity core AI07-06G from Trinity Bay, Newfoundland, recorded changes in the strength of the Labrador Current (LC) during the Holocene. From ca. 7.2–5.7 cal kyr BP, Trinity Bay’s seafloor was influenced by cooled Atlantic water derived from the West Greenland Current (WGC) Davis Strait branch, merging into the relatively cold LC. This Atlantic water influence gradually decreased after ca. 5.7 cal kyr BP, reaching a minimum at ca. 4.9 cal kyr BP. In contrast, surface temperatures were relatively low due to cold surface water dominated by sea ice and meltwater carried south by the LC. Icebergs from outlet glaciers around Baffin Bay were abundant in the LC prior to ca. 5.5 cal kyr BP. From ca. 4.9–2.9 cal kyr BP, bottom waters became slightly colder and salinity decreased, as increased mixing of the water column brought less saline surface waters towards the seafloor. This may be explained by a weaker North Atlantic subpolar gyre, transporting less Atlantic water from the WGC to the (outer) LC. Arctic meltwater transport was reduced as glacial melting decreased at the end of the Holocene Thermal Optimum. At ca. 2.9 cal kyr BP, bottom waters returned to colder, more stable conditions, indicating a slight decrease in bottom-water ventilation. After ca. 2.1 cal kyr BP, surface water temperatures dropped and sea ice flux increased. The seafloor of Trinity Bay saw warmer conditions, consistent with a stronger subpolar gyre and increased influx of Atlantic-sourced water.
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