Theory and Satellite Experiment for Critical Exponent alpha of lambda-Transition in Superfluid Helium

On the basis recent seven-loop perturbation expansion for nu^{-1} = 3/(2 - alpha) we perform a careful reinvestigation of the critical exponent alpha governing the power behavior |T_c-T|^{- alpha} of the specific heat of superfluid helium near the phase transition. With the help of variational strong-coupling theory. we find alpha = - 0.01126 +- 0.0010, in very good agreement with the space shuttle experimental value alpha = - 0.01056 +- 0.00038.Comment: Final version to be printed in Phys. Lett. A. Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/28

The symmetries of the Manton superconductivity model

The symmetries and conserved quantities of Manton's modified superconductivity model with non-relativistic Maxwell-Chern-Simons dynamics (also related to the Quantized Hall Effect) are obtained in the ``Kaluza-Klein type'' framework of Duval et al.Comment: 24 pages, Plain TEX, no figure

Interfacial accumulation of self-propelled Janus colloids in sessile droplets

Living microorganisms in confined systems typically experience an affinity to populate boundaries. The reason for such affinity to interfaces can be a combination of their directed motion and hydrodynamic interactions at distances larger than their own size. Here we will show that self-propelled Janus particles (polystyrene particles partially coated with platinum) immersed in droplets of water and hydrogen peroxide tend to accumulate in the vicinity of the liquid/gas interface. Interestingly, the interfacial accumulation occurs despite the presence of an evaporation-driven flow caused by a solutal Marangoni flow, which typically tends to redistribute the particles within the droplet's bulk. By performing additional experiments with passive colloids (flow tracers) and comparing with numerical simulations for both particle active motion and the fluid flow, we disentangle the dominating mechanisms behind the observed interfacial particle accumulation. These results allow us to make an analogy between active Janus particles and some biological microswimmers concerning how they interact with their environment.Comment: 9 pages, 7 figure

Personality traits and hardiness as risk- and protective factors for mental distress during the COVID-19 pandemic: a Norwegian two-wave study

Background Several risk factors for anxious-depressive symptomatology during the COVID-19 pandemic have been established. However, few studies have examined the relationship between personality traits, hardiness, and such symptomatology during the pandemic. These constructs might serve as risk- and/or protective factors for such mental distress through the pandemic. Methods A sample of 5783 Norwegians responded to a survey at two time points within the first year of the pandemic. The first data collection was in April 2020 (T1) and the second in December 2020 (T2). Measures included the Ten-Item Personality-Inventory, the Revised Norwegian Dispositional Resilience Scale, and the Patient Health Questionnaire Anxiety and Depression Scale. Analyses were performed using Pearson’s correlations, multiple linear regression, and a moderation analysis. Results Anxious-depressive symptomatology in early phases (T1) of the pandemic was the strongest predictor for the presence of such symptomatology 9 months after the outbreak (T2). Personality and hardiness correlated significantly with mental distress at T1 and T2. Personality traits explained 5% variance in symptoms when controlling for age, gender, solitary living, negative economic impact, and mental distress at baseline. Higher neuroticism predicted higher mental distress, whereas higher conscientiousness and extraversion predicted less mental distress. Hardiness did not explain variance in outcome beyond personality traits. Hardiness did not significantly moderate the relationship between neuroticism and mental distress. Conclusion Individuals with high levels of neuroticism had greater difficulties adapting to the circumstances of the COVID-19 pandemic and were more prone to mental distress. Contrastingly, higher conscientiousness and extraversion may have served as protective factors for mental distress during the pandemic. The current findings might aid identification of vulnerable individuals and groups. Consequently, preventive interventions could be offered to those who need it the most.publishedVersio

Recursive Graphical Construction for Feynman Diagrams of Quantum Electrodynamics

We present a method for a recursive graphical construction of Feynman diagrams with their correct multiplicities in quantum electrodynamics. The method is first applied to find all diagrams contributing to the vacuum energy from which all n-point functions are derived by functional differentiation with respect to electron and photon propagators, and to the interaction. Basis for our construction is a functional differential equation obeyed by the vacuum energy when considered as a functional of the free propagators and the interaction. Our method does not employ external sources in contrast to traditional approaches.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/29

Prion protein in the cerebrospinal fluid of healthy and naturally scrapie-affected sheep

The aim of this study was to characterize the cerebrospinal fluid (CSF) prion protein (PrP) of healthy and naturally scrapie-affected sheep. The soluble form of CSF PrPC immunoblotted with an anti-octarepeat and an anti-C terminus mAb showed two isoforms of approximately 33 and 26 kDa, corresponding to the biglycosylated and unglycosylated isoforms of brain PrPC. Neither the mean concentration nor the electrophoretic profile of CSF PrP differed between healthy and scrapieaffected sheep, whereas a slightly increased resistance of CSF PrP to mild proteolysis by proteinase K was evident in the CSF of scrapie-affected sheep. No difference in susceptibility to proteolysis was observed between the two ARR and VRQ genetic variants of the purified prokaryote recombinant PrP. It was concluded that the physicochemical properties of PrPC in the CSF could be altered during scrapie and that these changes might reflect the physiopathological process of prion disease

Changes in mental health symptoms from April (COVID-19 outbreak) to December 2020 in Norway: A two-wave study

The main objective of the study was to investigate changes in mental health symptoms from the start of the pandemic in Norway (April) to December 2020. A total of 6017 participants completed an assessment of the survey at both time points. Main Outcome Measures: Symptoms of anxiety and depression were measured at both time points. Demographic variables and potential risk factors were assessed. There were significant changes (slight increase) in anxiety and depression, but effect sizes were small. Increases in symptoms in anxiety and depression occurred more in the general population than for people with pre-existing mental health problems. Baseline level of symptoms was the most important risk factor. Other significant risk factors included female sex, students, pre-existing mental health problems, increased tobacco use, lost job, and lacking government trust. The longitudinal results replicated findings from the first phase of the pandemic, suggesting that the number of risk factors experienced is associated with symptom severity. The results suggest that mental health symptoms have been quite stable from April to December but with a slight increase among people presenting with subclinical symptoms in April.publishedVersio

Supersymmetry of the Schrodinger and PP Wave Solutions in Einstein-Weyl Supergravities

We obtain the Schrodinger and general pp-wave solutions with or without the massive vector in Einstein-Weyl supergravity. The vector is an auxiliary field in the off-shell supermultiplet and it acquires a kinetic term in the Weyl-squared super invariant. We study the supersymmetry of these solutions and find that turning on the massive vector has a consequence of breaking all the supersymmetry. The Schrodinger and also the pp-wave solutions with the massive vector turned off on the other hand preserve 1/4 of the supersymmetry.Comment: 13 pages, no figur