Solar Monte Carlo Radiative Transfer Simulations in Saharan Dust Plumes

Radiative fields of three-dimensional inhomogeneous Saharan dust clouds have been calculated at solar wavelengths by means of a Monte Carlo radiative transfer model. Scattering properties are taken from measurements in the SAMUM campaigns, from light scattering calculations for spheroids based on the MISCHKA code, from Mie Theory for spheres and from the Geometric Optics Method assuming irregular shaped particles. Optical properties of particles with different projected area equivalent shapes are compared. Large differences in optical properties are found especially in the phase functions. Modelled scattering properties are compared to laboratory measurements with good agreement. Results of radiative transfer calculations based on the Monte Carlo Method are shown exemplarily for one dust cloud simulated by the cloud resolving atmospheric circulation model COSMO-MUSCAT. Shape induced differences in the radiation fluxes are pronounced, for example, the domain averaged normalized radiance is about 20% lower in the case of a dust plume consisting of spheroids or irregular particles compared to spheres. Further the modelled radiative fields are compared to simulated fields from COSMO-MUSCAT and to satellite measurements with the SEVIRI instrument onbord the MSG satellite. In some cases the patterns of the radiative fields agree quiet well, especially with the simulated fields from COSMO-MUSCAT. But because by uncertainties in particular in the input data, the modelled radiative fields do not agree very well with most of the satellite measured fields. The satellite measurements are also used to compare with the measured radiances from an aircraft. There good agreements are found. In the Monte Carlo radiative transfer calculations the horizontal photon transport can be switched of, which was used for investigations on its effect (3D-effect) on the reflected radiance fields. The 3D-effect is only notable at the largest gradients in optical thickness. For example, the reflectance at low sun position differs locally about 25% when horizontal photon transport is accounted for. 'Sharp edges' due to 1D calculations are smoothed out in the 3D case

Clinical correlates of anti-SARS-CoV-2 antibody profiles in Spanish COVID-19 patients from a high incidence region

Laboratory testing for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) consists of two pillars: the detection of viral RNA via rt-PCR as the diagnostic gold standard in acute cases, and the detection of antibodies against SARS-CoV-2. However, concerning the latter, questions remain about their diagnostic and prognostic value and it is not clear whether all patients develop detectable antibodies. We examined sera from 347 Spanish COVID-19 patients, collected during the peak of the epidemic outbreak in Spain, for the presence of IgA and IgG antibodies against SARS-CoV-2 and evaluated possible associations with age, sex and disease severity (as measured by duration of hospitalization, kind of respiratory support, treatment in ICU and death). The presence and to some degree the levels of anti-SARS-CoV-2 antibodies depended mainly on the amount of time between onset of symptoms and the collection of serum. A subgroup of patients did not develop antibodies at the time of sample collection. Compared to the patients that did, no differences were found. The presence and level of antibodies was not associated with age, sex, duration of hospitalization, treatment in the ICU or death. The case-fatality rate increased exponentially with older age. Neither the presence, nor the levels of anti-SARS-CoV-2 antibodies served as prognostic markers in our cohort. This is discussed as a possible consequence of the timing of the sample collection. Age is the most important risk factor for an adverse outcome in our cohort. Some patients appear not to develop antibodies within a reasonable time frame. It is unclear, however, why that is, as these patients differ in no respect examined by us from those who developed antibodies

Solar radiative transfer simulations in Saharan dust plumes: particle shapes and 3-D effect

Radiative fields of three-dimensional inhomogeneous Saharan dust clouds have been calculated at solar wavelength (0.6 μm) by means of a Monte Carlo radiative transfer model. Scattering properties are taken from measurements in the SAMUM campaigns, from light scattering calculations for spheroids based on the MIESCHKA code, from Mie theory for spheres and from the geometric optics method assuming irregular shaped particles. Optical properties of different projected area equivalent shapes are compared. Large differences in optical properties are found especially in the phase functions. Results of radiative transfer calculations based on the Monte Carlo method are shown exemplarily for one dust cloud simulated by the cloud resolving atmospheric circulation model LM-MUSCAT-DES. Shape-induced differences in the radiation fluxes are pronounced, for example, the domain averaged normalized radiance is about 30% lower in the case of a dust plume consisting of spheroids or irregular particles compared to spheres. The effect of net horizontal photon transport (3-D effect) on the reflected radiance fields is only notable at the largest gradients in optical thickness. For example, the reflectance at low sun position differs locally about 15% when horizontal photon transport is accounted for. ‘Sharp edges' due to 1-D calculations are smoothed out in the 3-D case

Solare Monte Carlo Strahlungstransportsimulationen in Saharastaubwolken

Radiative fields of three-dimensional inhomogeneous Saharan dust clouds have been calculated at solar wavelengths by means of a Monte Carlo radiative transfer model. Scattering properties are taken from measurements in the SAMUM campaigns, from light scattering calculations for spheroids based on the MISCHKA code, from Mie Theory for spheres and from the Geometric Optics Method assuming irregular shaped particles. Optical properties of particles with different projected area equivalent shapes are compared. Large differences in optical properties are found especially in the phase functions. Modelled scattering properties are compared to laboratory measurements with good agreement. Results of radiative transfer calculations based on the Monte Carlo Method are shown exemplarily for one dust cloud simulated by the cloud resolving atmospheric circulation model COSMO-MUSCAT. Shape induced differences in the radiation fluxes are pronounced, for example, the domain averaged normalized radiance is about 20% lower in the case of a dust plume consisting of spheroids or irregular particles compared to spheres. Further the modelled radiative fields are compared to simulated fields from COSMO-MUSCAT and to satellite measurements with the SEVIRI instrument onbord the MSG satellite. In some cases the patterns of the radiative fields agree quiet well, especially with the simulated fields from COSMO-MUSCAT. But because by uncertainties in particular in the input data, the modelled radiative fields do not agree very well with most of the satellite measured fields. The satellite measurements are also used to compare with the measured radiances from an aircraft. There good agreements are found. In the Monte Carlo radiative transfer calculations the horizontal photon transport can be switched of, which was used for investigations on its effect (3D-effect) on the reflected radiance fields. The 3D-effect is only notable at the largest gradients in optical thickness. For example, the reflectance at low sun position differs locally about 25% when horizontal photon transport is accounted for. 'Sharp edges' due to 1D calculations are smoothed out in the 3D case.Die solaren Strahlungsfelder einer dreidimensionalen Saharastaubwolke wurden mit einem Monte Carlo Strahlungstransportmodellberechnet. Die benötigten Streueigenschaften wurden aus Messungen in den SAMUM Kampangen ermittelt und durch Lichtstreuberechnungen, für Spheroide basierend auf dem MISCHKA Code, für Kugeln mithilfe von Mie Theorie und mit der Methode der geometrischen Optik für irregulär geformte Teilchen ergänzt. Die optischen Eigenschaften von Partikeln mit unterschiedlichen Formen aber gleichen Projektionsflächen wurden verglichen und es wurden besonders in den Streufunktionen deutliche Unterschiede fest gestellt. Modellierte Streueigenschaften wurden mit Labormessungen verglichen und gute Übereinstimmungen konnten festgestellt werden. Die Ergebnisse der Strahlungstransportrechnungen mit der Monte Carlo Methode wurden exemplarisch für eine Staubwolke gezeigt, die vom Wolken auflösenden athmosphärischen Zirkulationsmodell COSMO-MUSCAT simuliert wurde. Ausgeprägte forminduzierte Unterschiede in den Strahlungsflüssen sind beispielsweise in den normierten Strahldichten, die über das Modellgebiet gemittelt wurden, vorhanden. Bei einer Staubwolke aus elliptischen oder unregelmäßigen Teilchen sind diese ungefähr 20% kleiner als bei Staubwolken, die aus kugelförmigen Teilchen bestehen. Weiterhin werden die modellierten Strahlungsfelder mit simulierten Feldern aus COSMO-MUSCAT und Satelliten-Messungen des MSG-Satelliten verglichen. Vor allen mit den den simulierten Strahlungsfeldern aus COSMO-MUSCAT stimmen die Monte Carlo modellierten Felder gut überein. Durch Unsicherheiten, insbesondere in den Eingabedaten, stimmen die modellierten Strahlungsfelder jedoch nicht sehr gut mit den vom Satelliten gemessenen Feldern überein. Die Satelliten-Messungen werden auch verwendet, um sie mit den Radianzen aus Flugzeugmessungen zu vergleichen, wobei sich gute Übereinstimmungen ergaben. In den Monte Carlo Strahlungstransportrechnungen kann der horizontale Photonentransport aus geschaltet werden. Dies wurde für Untersuchungen seines Einflusses (3D-Effekt) auf die reflektierten Strahldichtefelder eingesetzt. Der 3D-Effekt ist nur an den größten Gradienten der optischen Dicke relevant. Zum Beispiel unterscheidet sich das Reflexionsvermögen bei niedrigen Sonnenstand lokal um etwa 25%, wenn der horizontale Photonentransport berücksichtigt wird. "Scharfe Kanten" aufgrund der 1D Berechnungen werden in der 3D-Variante geglättet

The influence of sampling time on indirect reference limits, decision limits, and the estimation of biological variation of random plasma glucose concentrations

Objectives: Plasma glucose concentrations exhibit a pronounced daytime-dependent variation. The oscillations responsible for this are currently not considered in the determination of reference limits (RL) and decision limits. Methods: We characterized the daily variation inherent in large-scale laboratory data from two different university hospitals (site 1 n=513,682, site 2 n=204,001). Continuous and distinct RL for daytime and night were estimated. Diurnal characteristics of glucose concentrations were further investigated by quantile regression analyses introducing age and cosinor-functions as predictors in the model. Results: Diurnal variations expressed as amplitude/Midline Estimating Statistic of Rhythm (MESOR) ratio, averaged 7.7% (range 5.9-9.3%). The amplitude of glucose levels decreased with increasing concentrations. Between 06:00 and 10:00 h an average decrease of 4% has to be considered. Nocturnal glucose samples accounted for only 5% of the total amount but contributed to 19.5% of all findings over 11.1 mmol/L. Partitioning of RL between day and night is merely justified for the upper reference limit. The nocturnal upper RLs for both genders differed from those obtained during the day by 11.0 and 10.6% at site 1 and by 7.6 and 7.5% at site 2. Conclusions: We conclude that indirect approaches to estimate upper RL of random plasma glucose concentrations require stratification concerning the time of sample collection

Stimulus awareness is associated with secondary somatosensory cortex activation in an inattentional numbness paradigm

Abstract While inattentional blindness and deafness studies have revealed neural correlates of consciousness (NCC) without the confound of task relevance in the visual and auditory modality, comparable studies for the somatosensory modality are lacking. Here, we investigated NCC using functional magnetic resonance imaging (fMRI) in an inattentional numbness paradigm. Participants (N = 44) received weak electrical stimulation on the left hand while solving a demanding visual task. Half of the participants were informed that task-irrelevant weak tactile stimuli above the detection threshold would be applied during the experiment, while the other half expected stimuli below the detection threshold. Unexpected awareness assessments after the experiment revealed that altogether 10 participants did not consciously perceive the somatosensory stimuli during the visual task. Awareness was not significantly modulated by prior information. The fMRI data show that awareness of stimuli led to increased activation in the contralateral secondary somatosensory cortex. We found no significant effects of stimulus awareness in the primary somatosensory cortex or frontoparietal areas. Thus, our results support the hypothesis that somatosensory stimulus awareness is mainly based on activation in higher areas of the somatosensory cortex and does not require strong activation in extended anterior or posterior networks, which is usually seen when perceived stimuli are task-relevant