11 research outputs found
Periodicities of paleoclimate variations in the first high-resolution non-orbitally tuned grain size record of the past 1âŻMa from SW Hungary and regional, global correlations
This paper presents the results of grain-size analyses of an independently-dated loess/paleosol record dating back ca. 1âŻMa from SW Hungary. The record follows an upward coarsening trend with a clear prevalence of coarse silts and fine sands. Variations are mainly controlled by fluctuations in sand input highlighting iterative changes in dust aerodynamics over the past 1âŻMa in the source region found 50â100âŻkm NW of our site. Based on our results regional factors influenced the intensity and nature of dust accumulation. Contrasting trends with the Chinese Loess Plateau in certain periods reflect a greater importance of the Atlantic region driving the evolution of nearby continental ice sheets. Proximity and expansion of these had significant impact on local wind field. Low topography of the surrounding mountain belts allowed for the intrusion of stronger cold winds, higher abrasion in the source region and transportation of coarser particles to the site from 700 to 450âŻka. Another marked upward increase in grain-size from 400âŻka can be linked to increasing continentality which along with tectonic activity resulted in a drop in the groundwater table in the source region and intensified erosion of formerly relatively stable surfaces bringing more coarse material to our site
New chronology of the best developed loess/paleosol sequence of Hungary capturing the past 1.1 ma:Implications for correlation and proposed pan-Eurasian stratigraphic schemes
In this paper, we are presenting a revised chronology of the best developed, longest (100 m) LPS in Hungary dating back 1.1 Ma: borehole Udvari-2A. It is based on a non-tuned age-depth model, built on the position of the Matuyama-Brunhes Boundary, Jaramillo and Olduvai Subchrons. Furthermore, on the assignment of formerly recorded uninterpreted geomagnetic reversals in both chrons. Other chronometric tools (AMS 14C dating, biostratigraphy, tephrostratigraphy) yielding absolute ages and/or ensuring validation of these were also used. Records of a Middle Pleistocene gastropod index fossil Neostyriaca corynodes (400 -140 ka) facilitated verification of ages between MIS 10 and MIS 6. Multiple age control points at 15, 25, 27, 45, 120, 191, 362, 430, 670, 780, 900, 990, 1070 ka were established for the last ca. 1.1 Ma. The resulting chronology is the best resolved independent one so far among Danubian Basin LPSs. In light of our data, the S3-S4 units were fused as S3 in all Serbian, and some Romanian sites and re-correlated with MIS 9. The results also point to a misassignment of the S5 units at these sites to MIS 13â15 leading to erroneous conclusions regarding paleoclimatic conditions and cyclicity. In our new stratigraphic scheme, these S5 paleosols were taken to represent the S4 paleosol and recorrelated with MIS 11. Finally, an ideal stratigraphic column dating back 1.1 Ma for SW Hungary was constructed and correlated with the Chinese loess/paleosol sequence of Xifeng and the benthic oxygen isotope record down to MIS 31
New chronology and extended palaeoenvironmental data to the 1975 loess profile of Madaras brickyard, South Hungary
The 10m thick Madaras loessâpalaeosol profile is one of the Hungarian outcrops that yielded Upper Palaeolithic artefacts in 1966. To clarify the nature of the deposits and establish a reliable lithoâand chronostratigraphy, a profile was opened and sampled at 25cm intervals on the northern side of the brickyard in 1975. Analyses focused on grain size, carbonate content and the mollusc fauna. The chronology was based on the mollusc composition and a single date from the archaeological layer at the depth of ca 7m below the surface. The 1975 profile was destroyed by mining but the reposited samples allowed an extended analysis of this important Marine Isotope Stage 2 record to which archaeological features were directly assigned. A new absolute chronology was built based on 11 14C dates. Environmental magnetic, geochemical and palaeoecological investigations allowed a refined view of site evolution with reliable chronology for the Last Glacial Maximum. Our results corroborated those of previous investigations done on other coeval loessâpalaeosol sequences of the Southern Carpathian Basin. This also allowed for a temporal correlation to another local record with the published highâresolution chronology of the same brickyard and enabled modelling of localâscale heterogeneity of the environment in the long run
International eDelphi Study to Reach Consensus on the Methotrexate Dosing Regimen in Patients With Psoriasis
Importance: A clear dosing regimen for methotrexate in psoriasis is lacking, and this might lead to a suboptimal treatment. Because methotrexate is affordable and globally available, a uniform dosing regimen could potentially optimize the treatment of patients with psoriasis worldwide. Objective: To reach international consensus among psoriasis experts on a uniform dosing regimen for treatment with methotrexate in adult and pediatric patients with psoriasis and identify potential future research topics. Design, Setting, and Participants: Between September 2020 and March 2021, a survey study with a modified eDelphi procedure that was developed and distributed by the Amsterdam University Medical Center and completed by 180 participants worldwide (55 [30.6%] resided in non-Western countries) was conducted in 3 rounds. The proposals on which no consensus was reached were discussed in a conference meeting (June 2021). Participants voted on 21 proposals with a 9-point scale (1-3 disagree, 4-6 neither agree nor disagree, 7-9 agree) and were recruited through the Skin Inflammation and Psoriasis International Network and European Academy of Dermatology and Venereology in June 2020. Apart from being a dermatologist/dermatology resident, there were no specific criteria for participation in the survey. The participants worked mainly at a university hospital (97 [53.9%]) and were experienced in treating patients with psoriasis with methotrexate (163 [91.6%] had more than 10 years of experience). Main Outcomes and Measures: In a survey with eDelphi procedure, we tried to reach consensus on 21 proposals. Consensus was defined as less than 15% voting disagree (1-3). For the consensus meeting, consensus was defined as less than 30% voting disagree. Results: Of 251 participants, 180 (71.7%) completed all 3 survey rounds, and 58 participants (23.1%) joined the conference meeting. Consensus was achieved on 11 proposals in round 1, 3 proposals in round 2, and 2 proposals in round 3. In the consensus meeting, consensus was achieved on 4 proposals. More research is needed, especially for the proposals on folic acid and the dosing of methotrexate for treating subpopulations such as children and vulnerable patients. Conclusions and Relevance: In this eDelphi consensus study, consensus was reached on 20 of 21 proposals involving methotrexate dosing in patients with psoriasis. This consensus may potentially be used to harmonize the treatment with methotrexate in patients with psoriasis. © 2022 American Medical Association. All rights reserved