Capabilities of the Lamont–Doherty Earth Observatory in situ¹⁴C extraction laboratory updated

We report on the status and capabilities of the Lamont–Doherty Earth Observatory in situ¹⁴C extraction laboratory. In late 2006 we began, in collaboration with the AMS group at the University of Arizona, construction of a new laboratory to extract in situ cosmogenic ¹⁴C from terrestrial silicates. Long-term measurements of the process blank over the last two years give an arithmetic mean and standard deviation of 125 ± 43 × 10³ atoms ¹⁴C (n = 9) and show significant improvement in the number of atoms, as well as stability compared to initial measurements of the process blank. We report long-term measurements of the intercomparison material CRONUS-A, which has been developed as part of the CRONUS-Earth effort to characterize inter- and intra-laboratory variability. We interpret the standard deviation (5%) of six replicate measurements of CRONUS-A as the reproducibility of in situ¹⁴C extractions in our laboratory

Long‑term demise of sub‑Antarctic glaciers modulated by the Southern Hemisphere Westerlies

The accelerated melting of ice on the Antarctic Peninsula and islands in the sub-Antarctic suggests that the cryosphere is edging towards an irreversible tipping point. How unusual is this trend of ice loss within the frame of natural variability, and to what extent can it be explained by underlying climate dynamics? Here, we present new high-resolution reconstructions of long-term changes in the extents of three glaciers on the island of South Georgia (54°S, 36°W), combining detailed analyses of glacial-derived sediments deposited in distal glacier-fed lakes and cosmogenic exposure dating of moraines. We document that the glaciers of South Georgia have gradually retracted since the Antarctic cold reversal (ACR, 14.5–12.8 ka), culminating in the disappearance of at least one of the reconstructed glaciers. The glacier retreat pattern observed in South Georgia suggests a persistent link to summer insolation at 55°S, which intensified during the period from the ACR to approximately 2 ka. It also reveals multi-decadal to centennial climate shifts superimposed on this long-term trend that have resulted in at least nine glacier readvances during the last 10.5 ka. Accompanying meridional changes in the Southern Hemisphere westerlies and their interconnection with local topography may explain these glacier readvances.publishedVersio

Crystal Structure of an Anti-Ang2 CrossFab Demonstrates Complete Structural and Functional Integrity of the Variable Domain.

Bispecific antibodies are considered as a promising class of future biotherapeutic molecules. They comprise binding specificities for two different antigens, which may provide additive or synergistic modes of action. There is a wide variety of design alternatives for such bispecific antibodies, including the "CrossMab" format. CrossMabs contain a domain crossover in one of the antigen-binding (Fab) parts, together with the "knobs-and-holes" approach, to enforce the correct assembly of four different polypeptide chains into an IgG-like bispecific antibody. We determined the crystal structure of a hAng-2-binding Fab in its crossed and uncrossed form and show that CH1-CL-domain crossover does not induce significant perturbations of the structure and has no detectable influence on target binding

Holocene dynamics of the Rhone Glacier, Switzerland, deduced from ice flow models and cosmogenic nuclides

We describe efforts to model the Holocene extent of the Rhone Glacier, Switzerland, using four paleoclimate records as templates for paleo-equilibrium line altitude to identify candidate driving mechanisms of glaciers in the Alps. We evaluate the success of each paleoclimate template by comparing cosmogenic 10Be and 14C concentrations in pro-glacial bedrock derived from modeled glacier configurations to measured values. An adequate fit can be obtained using mean summer insolation for 46.5°N. However, use of the Dongee Cave, China, speleothem record yields the best fit by accounting for both sub-millennial (e.g. Little Ice Age and Medieval Warm Period) and multi-millennial climate variations (summer insolation). Our result indicates that glaciers in the Alps primarily responded to changes in insolation during the Holocene were smaller than today during the early Holocene when insolation was relatively high, and became larger during the mid to late Holocene. Superimposed on the first-order insolation response were shorter, sometimes large amplitude, length changes in response to short-lived climate events such as the Medieval Warm Period and the LIA

Toward Automated Feature Extraction for Deep Learning Classification of Electrocardiogram Signals

Many recent studies have focused on the automatic classification of electrocardiogram (ECG) signals using deep learning (DL) methods. Most rely on existing complex DL methods, such as transfer learning or providing the models with carefully designed extracted features based on domain knowledge. A common assumption is that the deeper and more complex the DL model is, the better it learns. In this study, we propose two different DL models for automatic feature extraction from ECG signals for classification tasks: A CNN-LSTM hybrid model and an attention/transformer-based model with wavelet transform for the dimensional embedding. Both of the models extract the features from time series at the initial layers of the neural networks and can obtain performance at least equal to, if not greater than, many contemporary deep neural networks. To validate our hypothesis, we used three publicly available data-sets to evaluate the proposed models. Our model achieved a benchmark accuracy of 99.92% for fall detection and 99.93% for the PTB database for myocardial infarction versus normal heartbeat classification

Glacier maxima in Baffin Bay during the Medieval Warm Period coeval with Norse settlement

The climatic mechanisms driving the shift from the Medieval Warm Period (MWP) to the Little Ice Age (LIA) in the North Atlantic region are debated. We use cosmogenic beryllium-10 dating to develop a moraine chronology with century-scale resolution over the last millennium and show that alpine glaciers in Baffin Island and western Greenland were at or near their maximum LIA configurations during the proposed general timing of the MWP. Complimentary paleoclimate proxy data suggest that the western North Atlantic region remained cool, whereas the eastern North Atlantic region was comparatively warmer during the MWP—a dipole pattern compatible with a persistent positive phase of the North Atlantic Oscillation. These results demonstrate that over the last millennium, glaciers approached their eventual LIA maxima before what is considered the classic LIA in the Northern Hemisphere. Furthermore, a relatively cool western North Atlantic region during the MWP has implications for understanding Norse migration patterns during the MWP. Our results, paired with other regional climate records, point to nonclimatic factors as contributing to the Norse exodus from the western North Atlantic region

Istraživanje nečiste i čiste (100) površine vanadija STM-om

Scanning tunneling microscopy is used to characterize different states of the V(100) surface during the cleaning procedure in an ultrahigh vacuum apparatus, starting with the "as received" sample and finishing with an almost perfectly clean surface. We show, for the first time, STM images of the clean V(100) surface and with atomic resolution.Primijenili smo skenirajući tunelirajući mikroskop (STM) za topografsku karakterizaciju površine V(100) prije i tijekom čišćenja u aparaturi za ultravisok vakuum, počevši s “dobivenim” uzorkom i nakon pojedinih postupaka čišćenja. Po prvi puta se pokazuju slike potpuno čiste površine V(100) s atomskim razlučivanjem, snimljene STM-om

Istraživanje nečiste i čiste (100) površine vanadija STM-om

Scanning tunneling microscopy is used to characterize different states of the V(100) surface during the cleaning procedure in an ultrahigh vacuum apparatus, starting with the "as received" sample and finishing with an almost perfectly clean surface. We show, for the first time, STM images of the clean V(100) surface and with atomic resolution.Primijenili smo skenirajući tunelirajući mikroskop (STM) za topografsku karakterizaciju površine V(100) prije i tijekom čišćenja u aparaturi za ultravisok vakuum, počevši s “dobivenim” uzorkom i nakon pojedinih postupaka čišćenja. Po prvi puta se pokazuju slike potpuno čiste površine V(100) s atomskim razlučivanjem, snimljene STM-om