2,556 research outputs found
Forecasting COVID-19 caseloads using unsupervised embedding clusters of social media posts
We present a novel approach incorporating transformer-based language models into infectious disease modelling. Text-derived features are quantified by tracking high-density clusters of sentence-level representations of Reddit posts within specific US states’ COVID-19 subreddits. We benchmark these clustered embedding features against features extracted from other high-quality datasets. In a threshold-classification task, we show that they outperform all other feature types at predicting upward trend signals, a significant result for infectious disease modelling in areas where epidemiological data is unreliable. Subsequently, in a time-series forecasting task, we fully utilise the predictive power of the caseload and compare the relative strengths of using different supplementary datasets as covariate feature sets in a transformer-based time-series model
Time Machine GPT
Large language models (LLMs) are often trained on extensive, temporally indiscriminate text corpora, reflecting the lack of datasets with temporal metadata. This approach is not aligned with the evolving nature of language. Conventional methods for creating temporally adapted language models often depend on further pre-training static models on time-specific data. This paper presents a new approach: a series of point-in-time LLMs called Time Machine GPT (TiMaGPT), specifically designed to be nonprognosticative. This ensures they remain uninformed about future factual information and linguistic changes. This strategy is beneficial for understanding language evolution and is of critical importance when applying models in dynamic contexts, such as time-series forecasting, where foresight of future information can prove problematic. We provide access to both the models and training datasets
Light-assisted ion-neutral reactive processes in the cold regime: radiative molecule formation vs. charge exchange
We present a combined experimental and theoretical study of cold reactive
collisions between laser-cooled Ca+ ions and Rb atoms in an ion-atom hybrid
trap. We observe rich chemical dynamics which are interpreted in terms of
non-adiabatic and radiative charge exchange as well as radiative molecule
formation using high-level electronic structure calculations. We study the role
of light-assisted processes and show that the efficiency of the dominant
chemical pathways is considerably enhanced in excited reaction channels. Our
results illustrate the importance of radiative and non-radiative processes for
the cold chemistry occurring in ion-atom hybrid traps.Comment: 5 pages, 4 figure
The Threat of Capital Drain: A Rationale for Public Banks?
This paper yields a rationale for why subsidized public banks may be desirable from a regional perspective in a financially integrated economy. We present a model with credit rationing and heterogeneous regions in which public banks prevent a capital drain from poorer to richer regions by subsidizing local depositors, for example, through a public guarantee. Under some conditions, cooperative banks can perform the same function without any subsidization; however, they may be crowded out by public banks. We also discuss the impact of the political structure on the emergence of public banks in a political-economy setting and the role of interregional mobility
Multi-Color Imaging of Magnetic Co/Pt Multilayers
We demonstrate for the first time the realization of a spatial resolved two color, element-specific imaging experiment at the free-electron laser facility FERMI. Coherent imaging using Fourier transform holography was used to achieve direct real space access to the nanometer length scale of magnetic domains of Co/Pt heterostructures via the element-specific magnetic dichroism in the extreme ultraviolet spectral range. As a first step to implement this technique for studies of ultrafast phenomena we present the spatially resolved response of magnetic domains upon femtosecond laser excitation
Ceramide remodeling and risk of cardiovascular events and mortality
BackgroundRecent studies suggest that circulating concentrations of specific ceramide species may be associated with coronary risk and mortality. We sought to determine the relations between the most abundant plasma ceramide species of differing acyl chain lengths and the risk of coronary heart disease (CHD) and mortality in community‐based samples. Methods and ResultsWe developed a liquid chromatography/mass spectrometry assay to quantify plasma C24:0, C22:0, and C16:0 ceramides and ratios of these very–long‐chain/long‐chain ceramides in 2642 FHS (Framingham Heart Study) participants and in 3134 SHIP (Study of Health in Pomerania) participants. Over a mean follow‐up of 6 years in FHS, there were 88 CHD and 90 heart failure (HF) events and 239 deaths. Over a median follow‐up time in SHIP of 5.75 years for CHD and HF and 8.24 years for mortality, there were 209 CHD and 146 HF events and 377 deaths. In meta‐analysis of the 2 cohorts and adjusting for standard CHD risk factors, C24:0/C16:0 ceramide ratios were inversely associated with incident CHD (hazard ratio per average SD increment, 0.79; 95% confidence interval, 0.71–0.89; P<0.0001) and inversely associated with incident HF (hazard ratio, 0.78; 95% confidence interval, 0.61–1.00; P=0.046). Moreover, the C24:0/C16:0 and C22:0/C16:0 ceramide ratios were inversely associated with all‐cause mortality (C24:0/C16:0: hazard ratio, 0.60; 95% confidence interval, 0.56–0.65; P<0.0001; C22:0/C16:0: hazard ratio, 0.65; 95% confidence interval, 0.60–0.70; P<0.0001). ConclusionsThe ratio of C24:0/C16:0 ceramides in blood may be a valuable new biomarker of CHD risk, HF risk, and all‐cause mortality in the community
Upscaling of perovskite solar modules: The synergy of fully evaporated layer fabrication and all‐laser‐scribed interconnections
Given the outstanding progress in research over the past decade, perovskite photovoltaics (PV) is about to step up from laboratory prototypes to commercial products. For this to happen, realizing scalable processes to allow the technology to transition from solar cells to modules is pivotal. This work presents all-evaporated perovskite PV modules with all thin films coated by established vacuum deposition processes. A common 532-nm nanosecond laser source is employed to realize all three interconnection lines of the solar modules. The resulting module interconnections exhibit low series resistance and a small total lateral extension down to 160 μm. In comparison with interconnection fabrication approaches utilizing multiple scribing tools, the process complexity is reduced while the obtained geometrical fill factor of 96% is comparable with established inorganic thin-film PV technologies. The all-evaporated perovskite minimodules demonstrate power conversion efficiencies of 18.0% and 16.6% on aperture areas of 4 and 51 cm, respectively. Most importantly, the all-evaporated minimodules exhibit only minimal upscaling losses as low as 3.1% per decade of upscaled area, at the same time being the most efficient perovskite PV minimodules based on an all-evaporated layer stack sequence
Role of Kozak sequence polymorphism of platelet glycoprotein Ibα as a risk factor for coronary artery disease and catheter interventions
AbstractOBJECTIVESWe sought to determine the role of the −5T/C polymorphism of the platelet glycoprotein (GP) Ibα as a potential risk factor for coronary artery disease (CAD) and adverse events complicating a coronary catheter intervention.BACKGROUNDThe platelet GP Ib-IX-V receptor complex plays a crucial role in arterial thrombus formation. The −5T/C polymorphism of GP Ibα is associated with increased receptor density.METHODSWe genotyped 1,000 patients with angiographically confirmed CAD, as well as 1,000 age- and gender-matched control subjects, for this polymorphism by polymerase chain reaction/restriction fragment length polymorphism. Among the patients with CAD, 269 underwent percutaneous transluminal coronary angioplasty (PTCA), 103 underwent directional coronary atherectomy and 278 underwent stenting. This intervention group was followed for a 30-day composite end point of target vessel revascularization, myocardial infarction or death.RESULTSCarriers of the −5C allele were significantly over-represented in the group of patients developing acute coronary syndromes (relative risk [RR] 1.43, 95% confidence interval [CI] 1.05 to 1.95, p = 0.02). The −5C allele furthermore predicted an increased risk for developing complications after PTCA (RR 3.75, 95% CI 1.15 to 12.27, p = 0.029).CONCLUSIONSThe −5C allele of the GP Ibα Kozak polymorphism may represent a risk factor in clinical conditions in which thrombosis plays an important role, such as in acute coronary syndromes and in complications after PTCA
Recipient age and outcome after pancreas transplantation:a retrospective dual-center analysis
With a later onset of diabetes complications and thus increasing age of transplant candidates, many centers have extended upper age limits for pancreas transplantation. This study investigates the effect of recipient and donor age on outcomes after pancreas transplantation.We retrospectively analyzed 565 pancreas transplants performed at two Eurotransplant centers. The cohort was split at a recipient and donor age of 50 and 40 years, respectively. Median recipient age in old patients (≥50 years; 27.2%) was 54 years and 40 years in young patients (<50 years). Compared to young recipients, old recipients had an inferior patient survival rate (≥50: 5yr, 82.8%; 10yr, 65.6%; <50: 5yr, 93.3%; 10yr, 82.0%; P < 0.0001). Old recipients demonstrated comparable death-censored pancreas (≥50: 1yr, 80.6%; 5yr, 70.2%; <50: 1yr, 87.3%; 5yr, 77.8%; P = 0.35) and kidney graft survival (≥50: 1yr, 97.4%; 5yr, 90.6%; <50: 1yr, 97.8%; 5yr, 90.2%; P = 0.53) compared to young recipients. Besides a lower rate of kidney rejection, similar relative risks for postoperative complications were detected in old and young patients. This study shows that despite an increased mortality in old recipients, excellent graft survival can be achieved similar to that of young patients. Age alone should not exclude patients from receiving a pancreas transplant
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