Measuring a Kaluza-Klein radius smaller than the Planck length

Hestenes has shown that a bispinor field on a Minkowski space-time is equivalent to an orthonormal tetrad of one-forms together with a complex scalar field. More recently, the Dirac and Einstein equations were unified in a tetrad formulation of a Kaluza-Klein model which gives precisely the usual Dirac-Einstein Lagrangian. In this model, Dirac's bispinor equation is obtained in the limit for which the radius of higher compact dimensions of the Kaluza-Klein manifold becomes vanishingly small compared with the Planck length. For a small but finite radius, the Kaluza-Klein model predicts velocity splitting of single fermion wave packets. That is, the model predicts a single fermion wave packet will split into two wave packets with slightly different group velocities. Observation of such wave packet splits would determine the size of the Kaluza-Klein radius. If wave packet splits were not observed in experiments with currently achievable accuracies, the Kaluza-Klein radius would be at least twenty five orders of magnitude smaller than the Planck length

Hestenes' Tetrad and Spin Connections

Defining a spin connection is necessary for formulating Dirac's bispinor equation in a curved space-time. Hestenes has shown that a bispinor field is equivalent to an orthonormal tetrad of vector fields together with a complex scalar field. In this paper, we show that using Hestenes' tetrad for the spin connection in a Riemannian space-time leads to a Yang-Mills formulation of the Dirac Lagrangian in which the bispinor field is mapped to a set of Yang-Mills gauge potentials and a complex scalar field. This result was previously proved for a Minkowski space-time using Fierz identities. As an application we derive several different non-Riemannian spin connections found in the literature directly from an arbitrary linear connection acting on Hestenes' tetrad and scalar fields. We also derive spin connections for which Dirac's bispinor equation is form invariant. Previous work has not considered form invariance of the Dirac equation as a criterion for defining a general spin connection

Competing risks of cancer mortality and cardiovascular events in individuals with multimorbidity

Background: Cancer patients with cardiovascular and other comorbidities are at concurrent risk of multiple adverse outcomes. However, most treatment decisions are guided by evidence from single-outcome models, which may be misleading for multimorbid patients. Objective: We assessed the interacting effects of cancer, cardiovascular, and other morbidity burdens on the competing outcomes of cancer mortality, serious cardiovascular events, and other-cause mortality. Design: We analyzed a cohort of 6,500 adults with initial cancer diagnosis between 2001 and 2008, SEER 5-year survival ≥26%, and a range of cardiovascular risk factors. We estimated the cumulative incidence of cancer mortality, a serious cardiovascular event (myocardial infarction, coronary revascularization, or cardiovascular mortality), and other-cause mortality over 5 years, and identified factors associated with the competing risks of each outcome using cause-specific Cox proportional hazard models. Results: Following cancer diagnosis, there were 996 (15.3%) cancer deaths, 328 (5.1%) serious cardiovascular events, and 542 (8.3%) deaths from other causes. In all, 4,634 (71.3%) cohort members had none of these outcomes. Although cancer prognosis had the greatest effect, cardiovascular and other morbidity also independently increased the hazard of each outcome. The effect of cancer prognosis on outcome was greatest in year 1, and the effect of other morbidity was greater in individuals with better cancer prognoses. Conclusion: In multimorbid oncology populations, comorbidities interact to affect the competing risk of different outcomes. Quantifying these risks may provide persons with cancer plus cardiovascular and other comorbidities more accurate information for shared decision-making than risks calculated from single-outcome models. Journal of Comorbidity 2014:4(1):29–3

How Politics Shape Views Toward Fact-Checking: Evidence from Six European Countries

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this recordFact-checking has spread internationally, in part to confront the rise of digital disinformation campaigns. American studies suggests ideological asymmetry in attitudes towards factchecking, as well as greater acceptance of the practice among those more interested in and knowledgeable about politics. We examine attitudes toward fact-checking across 6 European counties to put these findings in a broader context (N = 6,067). We find greater familiarity with and acceptance of fact-checking in Northern Europe (Sweden, Germany) than elsewhere (Italy, Spain, France, Poland). We further find two dimensions of political antipathy: a left-right dimension and an “anti-elite” dimension (including dissatisfaction with democracy and negative feelings toward the E.U.), the latter of which more consistently predicts negative feelings toward fact-checkers in the countries examined. Our findings demonstrate that despite general acceptance of the movement, significant political divides remain. Those less likely to trust factcheckers could be more vulnerable to disinformation targeting these divides, leading to a spiral of cynicism.European Commissio

Social corrections act as a double-edged sword by reducing the perceived accuracy of false and real news in the UK, Germany, and Italy

This is the final version. Available from Nature Research via the DOI in this record. Data availability: All shareable data are found on the online OSF repository at https://osf.io/jhwfgCode availability: All the code including reproducible analyses are found on the online OSF repository at https://osf.io/4hjcf for data relating to the UK, https://osf.io/yvdj4 for Italy, and https:// osf.io/jhwfg Germany.Corrective or refutational posts from ordinary users on social media have the potential to improve the online information ecosystem. While initial evidence of these social corrections is promising, a better understanding of the effects across different topics, formats, and audiences is needed. In three pre-registered experiments (N = 1944 UK, N = 2467 Italy, N = 2210 Germany) where respondents completed a social media post assessment task with false and true news posts on various topics (e.g., health, climate change, technology), we find that social corrections reduce perceived accuracy of and engagement with false news posts. We also find that social corrections that flag true news as false decrease perceived accuracy of and engagement with true news posts. We did not find evidence to support moderation of these effects by correction strength, anti-expert sentiments, cognitive reflection capacities, or susceptibility to social influence. While social corrections can be effective for false news, they may also undermine belief in true news.British AcademyDavidson Colleg

On Clifford representation of Hopf algebras and Fierz identities

We present a short review of the action and coaction of Hopf algebras on Clifford algebras as an introduction to physically meaningful examples. Some q-deformed Clifford algebras are studied from this context and conclusions are derived.Comment: 27 pages, Latex2e, to appear in Found. of Phy

Partisanship and public opinion of COVID-19: Does emphasizing Trump and his administration’s response to the pandemic affect public opinion about the coronavirus?

This is the final version. Available on open access from Routledge via the DOI in this recordDoes emphasizing the pandemic as a partisan issue polarize factual beliefs, attitudes, and behavioral intentions concerning the SARS-CoV-2/COVID-19 pandemic? To answer this question, we conducted a preregistered survey experiment with a “questions as treatment” design in late March 2020 with 1,587 U.S. respondents recruited via Prime Panel. Respondents were randomly assigned to answer several questions about then-president Donald J. Trump and the coronavirus (including receiving an information cue by evaluating one of Trump’s tweets) either at the beginning of the survey (treated condition) or at the end of the survey (control condition). Receiving these questions at the beginning of the survey had no direct effect on COVID-19 factual beliefs, attitudes, and behavioral intentions.European Union Horizon 202

Kleinsäuger mit Haarproben zuverlässig bestimmen

Um das Vorkommen der Schweizer Kleinsäugetiere zu untersuchen, müssen diese lebend gefangen und bestimmt werden. Gewisse ähnliche Arten lassen sich jedoch morphologisch nicht genau unterscheiden. Für eine sichere Artbestimmung ist deshalb bei einigen Arten eine DNA-Analyse unumgänglich. Die Entnahme von Haarproben ermöglicht eine für das Tier schnelle und schonende Gewinnung von DNA

Analysing and predicting wildlife–vehicle collision hotspots for the Swiss road network

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Context: Wildlife–vehicle collisions (WVCs) are a significant threat for many species, cause financial loss and pose a serious risk to motorist safety. Objectives: We used spatial data science on regional collision data from Switzerland with the objectives of identifying the key environmental collision risk factors and modelling WVC risk on a nationwide scale. Methods: We used 43,000 collision records with roe deer, red deer, wild boar, and chamois from 2010 to 2015 for both midlands and mountainous landscape types. We compared a fixed-length road segmentation approach with segments based on Kernel Density Estimation, a data-driven segmentation method. The segments’ environmental properties were derived from land-cover geodata using novel neighbourhood operations. Multivariate logistic regression and random forest classifiers were used to identify and rank the relevant environmental factors and to predict collision risk in areas without collision data. Results: The key factors for WVC hotspots are road sinuosity, and two composite factors for browsing/forage availability and traffic noise—a proxy for traffic flow. Our best models achieved sensitivities of 82.5% to 88.6%, with misclassifications of 20.14% and 27.03%, respectively. Our predictions were better in forested areas and revealed limitations in open landscape due to lack of up-to-date data on annual crop changes. Conclusions: We illustrate the added value of using fine-grained land-cover data for WVC modelling, and show how such detailed information can be annotated to road segments using spatial neighbourhood functions. Finally, we recommend the inclusion of annual crop data for improving WVC modelling