211 research outputs found
Europium Underneath Graphene on Ir(111): Intercalation Mechanism, Magnetism, and Band Structure
The intercalation of Eu underneath Gr on Ir(111) is comprehensively
investigated by microscopic, magnetic, and spectroscopic measurements, as well
as by density functional theory. Depending on the coverage, the intercalated Eu
atoms form either a or a R superstructure with respect to Gr. We investigate the
mechanisms of Eu penetration through a nominally closed Gr sheet and measure
the electronic structures and magnetic properties of the two intercalation
systems. Their electronic structures are rather similar. Compared to Gr on
Ir(111), the Gr bands in both systems are essentially rigidly shifted to larger
binding energies resulting in n-doping. The hybridization of the Ir surface
state with Gr states is lifted, and the moire superperiodic potential is
strongly reduced. In contrast, the magnetic behavior of the two intercalation
systems differs substantially as found by X-ray magnetic circular dichroism.
The Eu structure displays plain paramagnetic behavior, whereas
for the R structure the large
zero-field susceptibility indicates ferromagnetic coupling, despite the absence
of hysteresis at 10 K. For the latter structure, a considerable easy-plane
magnetic anisotropy is observed and interpreted as shape anisotropy.Comment: 18 pages with 14 figures, including Supplemental Materia
Association between exercise frequency with renal and cardiovascular outcomes in diabetic and non-diabetic individuals at high cardiovascular risk
Background: Guidelines recommend physical activity to reduce cardiovascular (CV) events. The association between
physical activity and progression of chronic kidney disease (CKD) with and without diabetes is unknown. We assessed
the association of self-reported physical activity with renal and CV outcomes in high-risk patients agedâ„55 years over
a median follow-up of 56 months in post-hoc analysis of a previously randomized trial program.
Methods: Analyses were done with Cox regression analysis, mixed models for repeated measures, ANOVA and Ï2
-
test. 31,312 patients, among them 19,664 with and 11,648 without diabetes were analyzed.
Results: Physical activity was inversely associated with renal outcomes (doubling of creatinine, end-stage kidney
disease (ESRD)) and CV outcomes (CV death, myocardial infarction, stroke, heart failure hospitalization). Moderate
activity (at least 2 times/week to every day) was associated with lower risk of renal outcomes and lower incidence of
new albuminuria (p<0.0001 for both) compared to lower exercise levels. Similar results were observed for those with
and without diabetes without interaction for renal outcomes (p=0.097â0.27). Physical activity was associated with
reduced eGFR decline with a moderate association between activity and diabetes status (p=0.05).
Conclusions: Moderate physical activity was associated with improved kidney outcomes with a threshold at two
sessions per week. The association of physical activity with renal outcomes did not meaningfully difer with or without
diabetes but absolute beneft of activity was even greater in people with diabetes. Thus, risks were similar between
those with diabetes undertaking high physical activity and those without diabetes but low physical activity.
Clinical trial registration: http://clinicaltrials.gov.uniqueidentifer:NCT00153101
Association between exercise frequency with renal and cardiovascular outcomes in diabetic and non-diabetic individuals at high cardiovascular risk
Background: Guidelines recommend physical activity to reduce cardiovascular (CV) events. The association between physical activity and progression of chronic kidney disease (CKD) with and without diabetes is unknown. We assessed the association of self-reported physical activity with renal and CV outcomes in high-risk patients agedââ„â55Â years over a median follow-up of 56Â months in post-hoc analysis of a previously randomized trial program.
Methods
Analyses were done with Cox regression analysis, mixed models for repeated measures, ANOVA and Ï2-test. 31,312 patients, among them 19,664 with and 11,648 without diabetes were analyzed.
Results
Physical activity was inversely associated with renal outcomes (doubling of creatinine, end-stage kidney disease (ESRD)) and CV outcomes (CV death, myocardial infarction, stroke, heart failure hospitalization). Moderate activity (at least 2 times/week to every day) was associated with lower risk of renal outcomes and lower incidence of new albuminuria (pâ<â0.0001 for both) compared to lower exercise levels. Similar results were observed for those with and without diabetes without interaction for renal outcomes (pâ=â0.097â0.27). Physical activity was associated with reduced eGFR decline with a moderate association between activity and diabetes status (pâ=â0.05).
Conclusions
Moderate physical activity was associated with improved kidney outcomes with a threshold at two sessions per week. The association of physical activity with renal outcomes did not meaningfully differ with or without diabetes but absolute benefit of activity was even greater in people with diabetes. Thus, risks were similar between those with diabetes undertaking high physical activity and those without diabetes but low physical activity.
Clinical trial registration:
http://clinicaltrials.gov.uniqueidentifier
:NCT00153101
Real-time monitoring of COVID-19 dynamics using automated trend fitting and anomaly detection
As several countries gradually release social distancing measures, rapid detection of new localized COVID-19 hotspots and subsequent intervention will be key to avoiding large-scale resurgence of transmission. We introduce ASMODEE (automatic selection of models and outlier detection for epidemics), a new tool for detecting sudden changes in COVID-19 incidence. Our approach relies on automatically selecting the best (fitting or predicting) model from a range of user-defined time series models, excluding the most recent data points, to characterize the main trend in an incidence. We then derive prediction intervals and classify data points outside this interval as outliers, which provides an objective criterion for identifying departures from previous trends. We also provide a method for selecting the optimal breakpoints, used to define how many recent data points are to be excluded from the trend fitting procedure. The analysis of simulated COVID-19 outbreaks suggests ASMODEE compares favourably with a state-of-art outbreak-detection algorithm while being simpler and more flexible. As such, our method could be of wider use for infectious disease surveillance. We illustrate ASMODEE using publicly available data of National Health Service (NHS) Pathways reporting potential COVID-19 cases in England at a fine spatial scale, showing that the method would have enabled the early detection of the flare-ups in Leicester and Blackburn with Darwen, two to three weeks before their respective lockdown. ASMODEE is implemented in the free R package trendbreaker. This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Single-nanoparticle phase transitions visualized by four-dimensional electron microscopy
The advancement of techniques that can probe the behaviour of individual nanoscopic objects is of paramount importance
in various disciplines, including photonics and electronics. As it provides images with a spatiotemporal resolution,
four-dimensional electron microscopy, in principle, should enable the visualization of single-nanoparticle structural
dynamics in real and reciprocal space. Here, we demonstrate the selectivity and sensitivity of the technique by visualizing
the spin crossover dynamics of single, isolated metalâorganic framework nanocrystals. By introducing a small aperture in
the microscope, it was possible to follow the phase transition and the associated structural dynamics within a single
particle. Its behaviour was observed to be distinct from that imaged by averaging over ensembles of heterogeneous
nanoparticles. The approach reported here has potential applications in other nanosystems and those that undergo
(bio)chemical transformations
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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