Aquatic and terrestrial proxy evidence for Middle Pleistocene palaeolake and lake‐shore development at two Lower Palaeolithic sites of Schöningen, Germany

The archaeological sites in the open‐cast mine of Schöningen, Germany, represent outstanding archives for understanding Middle Pleistocene interglacial–glacial transitions and human adaption. Aquatic microfossil and pollen assemblages from the ‘Reinsdorf sequence’, likely correlated to Marine Isotope Stage 9, document environmental changes from a thermal maximum to succeeding glacial conditions recorded in two sequences of excavation sites 12 II and 13 II. Multi‐proxy analyses enable detailed reconstruction of lake‐shore and landscape developments despite variable microfossil preservation in changing carbonate‐ and organic‐rich deposits. Rich aquatic vegetation with abundant charophytes suggests repeated phases with water depths of 0.5–2 m at site 13 II, while even greater temporary depths are deduced for 12 II DB. Mesorheophilic and mesotitanophilic ostracod species indicate stream inflows with medium–low calcium contents of >18 mg Ca L –1 originating from nearby springs. Diatoms point to meso‐eutrophic conditions and an alkaline pH of the lake water. Interglacial conditions with thermophile forests but no aquatic microfossils preserved, suggesting a dry or only temporarily flooded site, mark the beginning of the sequence. Continuous presence of aquatic organisms and overall dominance of small tychoplanktonic diatoms during a subsequent cool steppe phase provide evidence for increased water depths and unstable habitats characterized by erosion and probably prolonged periods of lake ice cover. During the succeeding boreal forest‐steppe phase, surface runoff into the productive, shallow lake decreased due to a more extensive vegetation cover. Concurrently, intensified groundwater input in contact with the nearby salt wall caused elevated salinities. Following a lake level drop, stream inflows and lake levels increased again towards the end of the Reinsdorf sequence and promoted development of a diverse fauna and flora at the lake shore; thereby maintaining an attractive living and hunting environment for early humans during a phase of generally cooler temperatures and landscape instability at the transition into a glacial period

Aquatic and terrestrial proxy evidence for Middle Pleistocene palaeolake and lake‐shore development at two Lower Palaeolithic sites of Schöningen, Germany

The archaeological sites in the open‐cast mine of Schöningen, Germany, represent outstanding archives for understanding Middle Pleistocene interglacial–glacial transitions and human adaption. Aquatic microfossil and pollen assemblages from the ‘Reinsdorf sequence’, likely correlated to Marine Isotope Stage 9, document environmental changes from a thermal maximum to succeeding glacial conditions recorded in two sequences of excavation sites 12 II and 13 II. Multi‐proxy analyses enable detailed reconstruction of lake‐shore and landscape developments despite variable microfossil preservation in changing carbonate‐ and organic‐rich deposits. Rich aquatic vegetation with abundant charophytes suggests repeated phases with water depths of 0.5–2 m at site 13 II, while even greater temporary depths are deduced for 12 II DB. Mesorheophilic and mesotitanophilic ostracod species indicate stream inflows with medium–low calcium contents of >18 mg Ca L–1 originating from nearby springs. Diatoms point to meso‐eutrophic conditions and an alkaline pH of the lake water. Interglacial conditions with thermophile forests but no aquatic microfossils preserved, suggesting a dry or only temporarily flooded site, mark the beginning of the sequence. Continuous presence of aquatic organisms and overall dominance of small tychoplanktonic diatoms during a subsequent cool steppe phase provide evidence for increased water depths and unstable habitats characterized by erosion and probably prolonged periods of lake ice cover. During the succeeding boreal forest‐steppe phase, surface runoff into the productive, shallow lake decreased due to a more extensive vegetation cover. Concurrently, intensified groundwater input in contact with the nearby salt wall caused elevated salinities. Following a lake level drop, stream inflows and lake levels increased again towards the end of the Reinsdorf sequence and promoted development of a diverse fauna and flora at the lake shore; thereby maintaining an attractive living and hunting environment for early humans during a phase of generally cooler temperatures and landscape instability at the transition into a glacial period.Niedersächsisches Ministerium für Wissenschaft und Kultur http://dx.doi.org/10.13039/501100010570Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165

Echocardiographic Versus Invasive Aortic Valve Gradients In Different Clinical Scenarios.

BACKGROUND The role of echocardiography in deriving transvalvular mean-gradients from transaortic velocities in aortic stenosis (AS) and in degenerated surgical bioprosthetic valves (SVD) is well established. However, reports following surgical aortic valve replacement (SAVR), post-transcatheter aortic valve replacement (TAVR), and valve-in-valve-TAVR (ViV-TAVR) have cautioned against the use of echocardiography-derived mean-gradients to assess normal functioning bioprosthesis due to discrepancy compared to invasive measures in a phenomenon called discordance. METHODS In a multicenter study, intra-procedural echocardiographic and invasive mean-gradients in AS, SVD, post-native-TAVR, and post-ViV-TAVR were compared, when obtained concomitantly, and discharge echocardiographic gradients were recorded. Absolute discordance (intra-procedural echocardiographic - invasive mean-gradient) and percent discordance (intra-procedural echocardiographic - invasive mean-gradient/echocardiographic mean-gradient) were calculated. Multivariable regression analysis to determine variables independently associated with elevated post-procedure invasive gradients ≥20mmHg, absolute discordance >10mmHg, and discharge echocardiographic mean-gradient ≥20mmHg RESULTS: 5027 patients were included in the registry; 4725 native-TAVR and 302 ViV-TAVR. Intra-procedural concomitant echocardiographic and invasive mean-gradients were obtained pre-TAVR in AS (N=2418), pre-ViV-TAVR in SVD (N=101), in 77 post-ViV-TAVR, and in 823 post-TAVR. Echocardiographic and invasive mean-gradients demonstrated strong correlation (r=0.69) and agreement (bias: 0.11, 95% confidence interval (CI) -0.4-0.62) in AS, moderate correlation (r=0.56) and agreement (bias:1.08, 95% CI -2.53-4.59) in SVD, moderate correlation (r=0.61) and weak agreement (bias:6.47, 95% CI 5.08-7.85) post-ViV-TAVR, and weak correlation (r=0.18) and agreement (bias:3.41, 95% CI 3.16-3.65) post-TAVR. Absolute discordance occurs primarily in ViV-TVR, is not explained by STJ size, and increases with increasing echocardiographic mean gradient. Percent discordance in AS and SVD (1.3% and 4%, respectively) was lower compared to post-TAVR/ViV-TAVR (66.7% and 100%, respectively). Compared to self-expanding valves, balloon-expandable valves were independently associated with elevated discharge echocardiographic but lower invasive mean-gradient (odds ratio=3.411, 95% CI:1.482-7.852, p= 0.004 vs. OR=0.308, 95% CI:0.130-0.731, p=0.008, respectively). CONCLUSIONS Post TAVR/ViV-TAVR, echocardiography is discordant from invasive mean-gradients and absolute discordance increases with increasing echocardiographic mean-gradient and is not explained by STJ size. Percent discordance is significantly higher post-TAVR/ViV-TAVR than in AS and SVD. Post-TAVR/ViV-TAVR, poor correlation and wide limits of agreement suggest echocardiographic and invasive mean-gradients may not be used interchangeably and a high residual echocardiographic mean-gradient should be confirmed invasively before considering any additional procedure to "correct" the gradient. TAVR valve types have variable impact on echocardiographic and invasive mean-gradients

Comparison of Transvalvular Aortic Mean Gradients Obtained by Intraprocedural Echocardiography and Invasive Measurement in Balloon and Self-Expanding Transcatheter Valves.

Background Concerns about discordance between echocardiographic and invasive mean gradients after transcatheter aortic valve replacement (TAVR) with balloon-expandable valves (BEVs) versus self-expanding valves (SEVs) exist. Methods and Results In a multicenter study, direct-invasive and echocardiography-derived transvalvular mean gradients obtained before and after TAVR were compared as well as post-TAVR and discharge echocardiographic mean gradients in BEVs versus SEVs in 808 patients. Pre-TAVR, there was good correlation (R=0.614; P<0.0001) between direct-invasive and echocardiography-derived mean gradients and weak correlation (R=0.138; P<0.0001) post-TAVR. Compared with post-TAVR echocardiographic mean gradients, both valves exhibit lower invasive and higher discharge echocardiographic mean gradients. Despite similar invasive mean gradients, a small BEV exhibits higher post-TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post-TAVR and discharge mean gradients. An ejection fraction <50% (P=0.028) and higher Society of Thoracic Surgeons predicted risk of mortality score (P=0.007), but not invasive or echocardiographic mean gradient ≥10 mm Hg (P=0.378 and P=0.341, respectively), nor discharge echocardiographic mean gradient ≥20 mm Hg (P=0.393), were associated with increased 2-year mortality. Conclusions Invasively measured and echocardiography-derived transvalvular mean gradients correlate well in aortic stenosis but weakly post-TAVR. Post-TAVR, echocardiography overestimates transvalvular mean gradients compared with invasive measurements, and poor correlation suggests these modalities cannot be used interchangeably. Moreover, echocardiographic mean gradients are higher on discharge than post-TAVR in all valves. Despite similar invasive mean gradients, a small BEV exhibits higher post-TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post-TAVR and discharge mean gradients. Immediately post-TAVR, elevated echocardiographic-derived mean gradients should be assessed with caution and compared with direct-invasive mean gradients. A low ejection fraction and higher Society of Thoracic Surgeons score, but not elevated mean gradients, are associated with increased 2-year mortality