171 research outputs found
Recommended from our members
Modelling mineral dust emissions and atmospheric dispersion with MADE3 in EMAC v2.54
It was hypothesized that using mineral dust emission climatologies in global chemistry climate models (GCCMs), i.e. prescribed monthly-mean dust emissions representative of a specific year, may lead to misrepresentations of strong dust burst events. This could result in a negative bias of model dust concentrations compared to observations for these episodes. Here, we apply the aerosol microphysics submodel MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, third generation) as part of the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model. We employ two different representations of mineral dust emissions for our model simulations: (i) a prescribed monthly-mean climatology of dust emissions representative of the year 2000 and (ii) an online dust parametrization which calculates wind-driven mineral dust emissions at every model time step. We evaluate model results for these two dust representations by comparison with observations of aerosol optical depth from ground-based station data. The model results show a better agreement with the observations for strong dust burst events when using the online dust representation compared to the prescribed dust emissions setup. Furthermore, we analyse the effect of increasing the vertical and horizontal model resolution on the mineral dust properties in our model. We compare results from simulations with T42L31 and T63L31 model resolution (2.8āĆ2.8ā and 1.9āĆ1.9ā in latitude and longitude, respectively; 31 vertical levels) with the reference setup (T42L19). The different model versions are evaluated against airborne in situ measurements performed during the SALTRACE mineral dust campaign (Saharan Aerosol Long-range Transport and Aerosol-Cloud Interaction Experiment, JuneāJuly 2013), i.e. observations of dust transported from the Sahara to the Caribbean. Results show that an increased horizontal and vertical model resolution is able to better represent the spatial distribution of airborne mineral dust, especially in the upper troposphere (above 400āhPa). Additionally, we analyse the effect of varying assumptions for the size distribution of emitted dust but find only a weak sensitivity concerning these changes. The results of this study will help to identify the model setup best suited for future studies and to further improve the representation of mineral dust particles in EMAC-MADE3
The development and appraisal of a tool designed to find patients harmed by falsely labelled, falsified (counterfeit) medicines.
To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesFalsely labelled, falsified (counterfeit) medicines (FFCm's) are produced or distributed illegally and can harm patients. Although the occurrence of FFCm's is increasing in Europe, harm is rarely reported. The European Directorate for the Quality of Medicines & Health-Care (EDQM) has therefore coordinated the development and validation of a screening tool.The tool consists of a questionnaire referring to a watch-list of FFCm's identified in Europe, including symptoms of their use and individual risk factors, and a scoring form. To refine the questionnaire and reference method, a pilot-study was performed in 105 self-reported users of watch-list medicines. Subsequently, the tool was validated under "real-life conditions" in 371 patients in 5 ambulatory and in-patient care sites ("sub-studies"). The physicians participating in the study scored the patients and classified their risk of harm as "unlikely" or "probable" (cut-off level: presence of ā„2 of 5 risk factors). They assessed all medical records retrospectively (independent reference method) to validate the risk classification and documented their perception of the tool's value.In 3 ambulatory care sites (180 patients), the tool correctly classified 5 patients as harmed by FFCm's. The positive and negative likelihood ratios (LR+/LR-) and the discrimination power were calculated for two cut-off levels: a) 1 site (50 patients): presence of two risk factors (at 10% estimated health care system contamination with FFCm's): LRā+ā4.9/LR-0, post-test probability: 35%; b) 2 sites (130 patients): presence of three risk factors (at 5% estimated prevalence of use of non-prescribed medicines (FFCm's) by certain risk groups): LRā+ā9.7/LR-0, post-test probability: 33%. In 2 in-patient care sites (191 patients), no patient was confirmed as harmed by FFCm's. The physicians perceived the tool as valuable for finding harm, and as an information source regarding risk factors.This "decision aid" is a systematic tool which helps find in medical practice patients harmed by FFCm's. This study supports its value in ambulatory care in regions with health care system contamination and in certain risk groups. The establishment of systematic communication between authorities and the medical community concerning FFCm's, current patterns of use and case reports may sustain positive public health impacts.EDQ
Wavelength-scale errors in optical localization due to spin-orbit coupling of light
The precise determination of the position of point-like emitters and
scatterers using far-field optical imaging techniques is of utmost importance
for a wide range of applications in medicine, biology, astronomy, and physics.
Although the optical wavelength sets a fundamental limit to the image
resolution of unknown objects, the position of an individual emitter can in
principle be estimated from the image with arbitrary precision. This is used,
e.g., in stars' position determination and in optical super-resolution
microscopy. Furthermore, precise position determination is an experimental
prerequisite for the manipulation and measurement of individual quantum
systems, such as atoms, ions, and solid state-based quantum emitters. Here we
demonstrate that spin-orbit coupling of light in the emission of elliptically
polarized emitters can lead to systematic, wavelength-scale errors in the
estimate of the emitter's position. Imaging a single trapped atom as well as a
single sub-wavelength-diameter gold nanoparticle, we demonstrate a shift
between the emitters' measured and actual positions which is comparable to the
optical wavelength. Remarkably, for certain settings, the expected shift can
become arbitrarily large. Beyond their relevance for optical imaging
techniques, our findings apply to the localization of objects using any type of
wave that carries orbital angular momentum relative to the emitter's position
with a component orthogonal to the direction of observation.Comment: Main text 6 pages, Methods 8 pages, Extended data 9 pages,
Supplementary information 4 page
Profiles of cloud condensation nuclei, dust mass concentration, and ice-nucleating-particle-relevant aerosol properties in the Saharan Air Layer over Barbados from polarization lidar and airborne in situ measurements
The present study aims to evaluate lidar retrievals of cloud-relevant aerosol properties by using polarization lidar and coincident airborne in situ measurements in the Saharan Air Layer (SAL) over the Barbados region. Vertical profiles of the number concentration of cloud condensation nuclei (CCN), large particles (diameter d>500ānm), surface area, mass, and ice-nucleating particle (INP) concentration are derived from the lidar measurements and compared with CCN concentrations and the INP-relevant aerosol properties measured in situ with aircraft. The measurements were performed in the framework of the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in summer 2013.
The CCN number concentrations derived from lidar observations were up to a factor of 2 higher than the ones measured in situ aboard the research aircraft Falcon. Possible reasons for the difference are discussed. The number concentration of particles with a dry radius of more than 250ānm and the surface-area concentration obtained from the lidar observations and used as input for the INP parameterizations agreed well (<30ā%-50ā% deviation) with the aircraft measurements. In a pronounced lofted dust layer during summer (10 July 2013), the lidar retrieval yielded 100-300 CCN per cubic centimeter at 0.2ā% water supersaturation and 10-200 INPs per liter at -25āC. Excellent agreement was also obtained in the comparison of mass concentration profiles.
During the SALTRACE winter campaign (March 2014), the dust layer from Africa was mixed with smoke particles which dominated the CCN number concentration. This example highlights the unique lidar potential to separate smoke and dust contributions to the CCN reservoir and thus to identify the sensitive role of smoke in trade wind cumuli developments over the tropical Atlantic during the winter season
Persistence of immunity to SARS-CoV-2 over time in the ski resort Ischgl
Background In early March 2020, a SARS-CoV-2 outbreak in the ski resort Ischgl in Austria triggered the spread of SARS-CoV-2 throughout Austria and Northern Europe. In a previous study, we found that the seroprevalence in the adult population of Ischgl had reached 45% by the end of April, representing an exceptionally high level of local seropositivity in Europe. We performed a follow-up study in Ischgl, which is the first to show persistence of immunity and protection against SARS-CoV-2 and some of its variants at a community level. Methods Of the 1259 adults that participated in the baseline study, 801 have been included in the follow-up in November 2020. The study involved the analysis of binding and neutralizing antibodies and T cell responses. In addition, the incidence of SARS-CoV-2 and its variants in Ischgl was compared to the incidence in similar municipalities in Tyrol until April 2021. Findings For the 801 individuals that participated in both studies, the seroprevalence declined from 51.4% (95% confidence interval (CI) 47.9-54.9) to 45.4% (95% CI 42.0-49.0). Median antibody concentrations dropped considerably (5.345, 95% CI 4.833 - 6.123 to 2.298, 95% CI 2.141 - 2.527) but antibody avidity increased (17.02, 95% CI 16.49 - 17.94 to 42.46, 95% CI 41.06 - 46.26). Only one person had lost detectable antibodies and T cell responses. In parallel to this persistent immunity, we observed that Ischgl was relatively spared, compared to similar municipalities, from the prominent second COVID-19 wave that hit Austria in November 2020. In addition, we used sequencing data to show that the local immunity acquired from wild-type infections also helped to curb infections from variants of SARS-CoV-2 which spread in Austria since January 2021. Interpretation The relatively high level of seroprevalence (40-45%) in Ischgl persisted and might have been associated with the observed protection of Ischgl residents against virus infection during the second COVID-19 wave as well as against variant spread in 2021. Funding Funding was provided by the government of Tyrol and the FWF Austrian Science Fund
No. 8 - The Cuban Embargo: Policy Outlook after 50 Years
Organized and sponsored by the Dean Rusk Center for International Law and Policy, The Cuban Embargo: Policy Outlook after 50 Years was a daylong conference exploring issues related to the impact of trade sanctions imposed by the United States on Cuba, pathways to lifting the embargo and potential U.S.-Cuba trade opportunities. Ambassador JosƩ R, CabaƱas, the chief of mission at the Cuban Interests Section in Washinton, D.C., served as the keynote speaker for the event. The transcript of the conference proceedings has been edited for publication with the consent of the speakers
Cloud droplet number closure for tropical convective clouds during the ACRIDICON CHUVA campaign
The main objective of the ACRIDICON-CHUVA campaign in September 2014 was the investigation of aerosol-cloud-interactions in the Amazon Basin. Cloud properties near cloud base of growing convective cumuli were characterized by cloud droplet size distribution measurements using a cloud combination probe and a cloud and aerosol spectrometer. In the current study, an adiabatic parcel model was used to perform cloud droplet number closure studies for several flights in differently polluted air masses
Light induced single molecule frequency shift
Alight induced frequency shift of the 0-0 line was measured in two-photon excitation spectra of single diphenyloctatetraene molecules doped in a crystal matrix. The shifts were proportional to the laser power with a slope of about 600 MHz/W when the laser beam of about 300 mW power was focused to a diameter of 2 mu m. Significantly, the observed line broadenings were an order of magnitude smaller than the shifts. The effect is ascribed mainly to a ''fast'' energy exchange between a local vibration and thermal phonons created by the third harmonic C-H band absorption in the matrix, and partially to an ac Stark shift
MURC/Cavin-4 and cavin family members form tissue-specific caveolar complexes
Polymerase I and transcript release factor (PTRF)/Cavin is a cytoplasmic protein whose expression is obligatory for caveola formation. Using biochemistry and fluorescence resonance energy transferābased approaches, we now show that a family of related proteins, PTRF/Cavin-1, serum deprivation response (SDR)/Cavin-2, SDR-related gene product that binds to C kinase (SRBC)/Cavin-3, and muscle-restricted coiled-coil protein (MURC)/Cavin-4, forms a multiprotein complex that associates with caveolae. This complex can constitutively assemble in the cytosol and associate with caveolin at plasma membrane caveolae. Cavin-1, but not other cavins, can induce caveola formation in a heterologous system and is required for the recruitment of the cavin complex to caveolae. The tissue-restricted expression of cavins suggests that caveolae may perform tissue-specific functions regulated by the composition of the cavin complex. Cavin-4 is expressed predominantly in muscle, and its distribution is perturbed in human muscle disease associated with Caveolin-3 dysfunction, identifying Cavin-4 as a novel muscle disease candidate caveolar protein
Prospective Environmental Life Cycle Assessment of Nanosilver T-Shirts
A cradle-to-grave life cycle assessment (LCA) is performed to compare nanosilver T-shirts with conventional T-shirts with and without biocidal treatment. For nanosilver production and textile incorporation, we investigate two processes: flame spray pyrolysis (FSP) and plasma polymerization with silver co-sputtering (PlaSpu). Prospective environmental impacts due to increased nanosilver T-shirt commercialization are estimated with six scenarios. Results show significant differences in environmental burdens between nanoparticle production technologies: The "cradle-to-gate" climate footprint of the production of a nanosilver T-shirt is 2.70 kg of CO2-equiv (FSP) and 7.67-166 kg of CO2-equiv (PlaSpu, varying maturity stages). Production of conventional T-shirts with and without the biocide triclosan has emissions of 2.55 kg of CO2-equiv (contribution from triclosan insignificant). Consumer behavior considerably affects the environmental impacts during the use phase. Lower washing frequencies can compensate for the increased climate footprint of FSP nanosilver T-shirt production. The toxic releases from washing and disposal in the life cycle of T-shirts appear to be of minor relevance. By contrast, the production phase may be rather significant due to toxic silver emissions at the mining site if high silver quantities are require
- ā¦