| 1. |
- Evangelou, Evangelos, et al.
(författare)
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Genetic analysis of over 1 million people identifies 535 new loci associated with blood pressure traits.
- 2018
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 50:10, s. 1412-1425
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Tidskriftsartikel (refereegranskat)abstract
- High blood pressure is a highly heritable and modifiable risk factor for cardiovascular disease. We report the largest genetic association study of blood pressure traits (systolic, diastolic and pulse pressure) to date in over 1 million people of European ancestry. We identify 535 novel blood pressure loci that not only offer new biological insights into blood pressure regulation but also highlight shared genetic architecture between blood pressure and lifestyle exposures. Our findings identify new biological pathways for blood pressure regulation with potential for improved cardiovascular disease prevention in the future.
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| 2. |
- Wain, Louise V., et al.
(författare)
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Novel Blood Pressure Locus and Gene Discovery Using Genome-Wide Association Study and Expression Data Sets From Blood and the Kidney
- 2017
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Ingår i: Hypertension. - 0194-911X .- 1524-4563. ; 70:3, s. e4-e19
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Tidskriftsartikel (refereegranskat)abstract
- Elevated blood pressure is a major risk factor for cardiovascular disease and has a substantial genetic contribution. Genetic variation influencing blood pressure has the potential to identify new pharmacological targets for the treatment of hypertension. To discover additional novel blood pressure loci, we used 1000 Genomes Project-based imputation in 150 134 European ancestry individuals and sought significant evidence for independent replication in a further 228 245 individuals. We report 6 new signals of association in or near HSPB7, TNXB, LRP12, LOC283335, SEPT9, and AKT2, and provide new replication evidence for a further 2 signals in EBF2 and NFKBIA. Combining large whole-blood gene expression resources totaling 12 607 individuals, we investigated all novel and previously reported signals and identified 48 genes with evidence for involvement in blood pressure regulation that are significant in multiple resources. Three novel kidney-specific signals were also detected. These robustly implicated genes may provide new leads for therapeutic innovation.
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| 3. |
- Chen, Qiuyu, et al.
(författare)
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Satellite observations of gravity wave momentum flux in the mesosphere and lower thermosphere (MLT) : feasibility and requirements
- 2022
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 15:23, s. 7071-7103
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Tidskriftsartikel (refereegranskat)abstract
- In the recent decade it became evident that we need to revise our picture of how gravity waves (GWs) reach the mesosphere and lower thermosphere (MLT). This has consequences for our understanding not just of the properties of the GWs themselves, but in particular of the global circulation in the MLT. Information on spectral distribution, direction, and zonal mean GW momentum flux is required to test the theoretical and modeling findings. In this study, we propose a constellation of two CubeSats for observing mesoscale GWs in the MLT region by means of temperature limb sounding in order to derive such constraints. Each CubeSat deploys a highly miniaturized spatial heterodyne interferometer (SHI) for the measurement of global oxygen atmospheric band emissions. From these emissions, the 3-D temperature structure can be inferred. We propose obtaining four independent observation tracks by splitting the interferograms in the center and thus gaining two observation tracks for each satellite. We present a feasibility study of this concept based on self-consistent, high-resolution global model data. This yields a full chain of end-to-end (E2E) simulations incorporating (1) orbit simulation, (2) airglow forward modeling, (3) tomographic temperature retrieval, (4) 3-D wave analysis, and (5) GW momentum flux (GWMF) calculation. The simulation performance is evaluated by comparing the retrieved zonal mean GWMF with that computed directly from the model wind data. A major question to be considered in our assessment is the minimum number of tracks required for the derivation of 3-D GW parameters. The main result from our simulations is that the GW polarization relations are still valid in the MLT region and can thus be employed for inferring GWMF from the 3-D temperature distributions. Based on the E2E simulations for gaining zonal mean climatologies of GW momentum flux, we demonstrate that our approach is robust and stable, given a four-track observation geometry and the expected instrument noise under nominal operation conditions. Using phase speed and direction spectra we show also that the properties of individual wave events are recovered when employing four tracks. Finally, we discuss the potential of the proposed observations to address current topics in the GW research. We outline for which investigations ancillary data are required to answer science questions.
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| 4. |
- Griessbach, Sabine, et al.
(författare)
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Aerosol and cloud top height information of Envisat MIPAS measurements
- 2020
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 13:3, s. 1243-1271
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Tidskriftsartikel (refereegranskat)abstract
- Infrared limb emission instruments have a long history in measuring clouds and aerosol. In particular, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard ESA's Envisat provides 10 years of altitude-resolved global measurements. Previous studies found systematic overestimations and underestimations of cloud top heights for cirrus and polar stratospheric clouds. To assess the cloud top height information and to characterise its uncertainty for the MIPAS instrument we performed simulations for ice clouds, volcanic ash, and sulfate aerosol. From the simulation results we found that in addition to the known effects of the field-of-view that can lead to a cloud top height overestimation, and broken cloud conditions that can lead to underestimation, the cloud extinction also plays an important role. While for optically thick clouds the possible cloud top height overestimation for MIPAS reaches up to 1.6 km due to the field-of-view, for optically thin clouds and aerosol the systematic underestimation reaches 5.1 km. For the detection sensitivity and the degree of underestimation of the MIPAS measurements, the cloud layer thickness also plays a role; 1 km thick clouds are detectable down to extinctions of 5 x 10(-4) km(-1) and 6 km thick clouds are detectable down to extinctions of 1 x 10(-4) km(-1), where the largest underestimations of the cloud top height occur for the optically thinnest clouds with a vertical extent of 6 km. The relation between extinction coefficient, cloud top height estimate, and layer thickness is confirmed by a comparison of MIPAS cloud top heights of the volcanic sulfate aerosol from the Nabro eruption in 2011 with space- and ground-based lidar measurements and twilight measurements between June 2011 and February 2012. For plumes up to 2 months old, where the extinction was between 1 x 10(-4) and 7 x 10(-4) km(-1) and the layer thickness mostly below 4 km, we found for MIPAS an average underestimation of 1.1 km. In the aged plume with extinctions down to 5 x 10(-5) km(-1) and layer thicknesses of up to 9.5 km, the underestimation was higher, reaching up to 7.2 km. The dependency of the cloud top height overestimations or underestimations on the extinction coefficient can explain seemingly contradictory results of previous studies. In spite of the relatively large uncertainty range of the cloud top height, the comparison of the detection sensitivity towards sulfate aerosol between MIPAS and a suite of widely used UV/VIS limb and IR nadir satellite aerosol measurements shows that MIPAS provides complementary information in terms of detection sensitivity.
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| 5. |
- Khosrawi, Farahnaz, et al.
(författare)
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Assessment of the interannual variability and influence of the QBO and upwelling on tracer-tracer distributions of N2O and O3 in the tropical lower stratosphere
- 2013
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:7, s. 3619-3641
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Tidskriftsartikel (refereegranskat)abstract
- A modified form of tracer-tracer correlations of N2O and O3 has been used as a tool for the evaluation of atmospheric photochemical models. Applying this method monthly averages of N2O and O3 are derived for both hemispheres by partitioning the data into altitude (or potential temperature) bins and then averaging over a fixed interval of N2O. In a previous study, the method has been successfully applied to the validation of two Chemical Transport Models (CTMs) and one Chemistry-Climate Model (CCM) using 1-year climatology derived from the Odin Sub Millimetre Radiometer (Odin/SMR). However, the applicability of a 1-year climatology of monthly averages of N2O and O3 has been questioned due to the inability of some CCMs to simulate a specific year for the evaluation of CCMs. In this study, satellite measurements from Odin/SMR, the Aura Microwave Limb Sounder (Aura/MLS), the Michelson Interferometer for Passive Atmospheric Sounding on ENVISAT (ENVISAT/MIPAS), and the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA-1 and CRISTA-2) as well as model simulations from the Whole Atmosphere Community Climate Model (WACCM) are considered. By using seven to eight years of satellite measurements derived between 2003 and 2010 from Odin/SMR, Aura/MLS, ENVISAT/MIPAS and six years of model simulations from WACCM the interannual variability of lower stratospheric monthly averages of N2O and O3 is assessed. It is shown that the interannual variability of the monthly averages of N2O and O3 is low and thus can be easily distinguished from model deficiencies. Further, it is investigated why large differences between Odin/SMR observations and model simulations from the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA) and the atmospheric general circulation model ECHAM5/Messy1 are found for the Northern and Southern Hemisphere tropics (0° to 30° N and 0° to −30° S, respectively). The differences between model simulations and observations are most likely caused by an underestimation of the quasi-biennial oscillation and tropical upwelling by the models as well as due to biases and/or instrument noise from the satellite instruments. Finally, an inter-comparison between Odin/SMR, Aura/MLS, ENVISAT/MIPAS and WACCM was performed. The comparison shows that these data sets are generally in good agreement but that also some known biases of the data sets are clearly visible in the monthly averages, thus showing that this method is not only a valuable tool for model evaluation but also for satellite inter-comparisons.
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| 6. |
- Khosrawi, Farahnaz, et al.
(författare)
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Intercomparison between Lagrangian and Eulerian simulations of mid-latitude streamers as observed by CRISTA
- 2005
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Ingår i: Atmospheric Chemistry and Physics. ; 5, s. 85-95
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Tidskriftsartikel (refereegranskat)abstract
- During the CRISTA-1 mission three pronounced fingerlike structures reaching from the lower latitudes to the mid-latitudes, so-called streamers, were observed in the measurements of several trace gases in early November 1994. A simulation of these streamers in previous studies employing the KASIMA (Karlsruhe Simulation Model of the Middle Atmosphere) and ROSE (Research on Ozone in the Stratosphere and its Evolution) model, both being Eulerian models, show that their formation is due to adiabatic transport processes. Here, the impact of mixing on the development of these streamers is investigated. These streamers were simulated with the CLaMS model (Chemical Lagrangian Model of the Stratosphere), a Lagrangian model, using N2O as longlived tracer. Using several different initialisations the results were compared to the KASIMA simulations and CRISTA (Cryogenic Infrared Spectrometer and Telescope for the Atmosphere) observations. Further, since the KASIMA model was employed to derive a 9-year climatology, the quality of the reproduction of streamers from such a study was tested by the comparison of the KASIMA results with CLaMS and CRISTA. The streamers are reproduced well for the Northern Hemisphere in the simulations of CLaMS and KASIMA for the 6 November 1994. However, in the CLaMS simulation a stronger filamentation is found while larger discrepancies between KASIMA and CRISTA were found especially for the Southern Hemisphere. Further, compared to the CRISTA observations the mixing ratios of N2O are in general underestimated in the KASIMA simulations. An improvement of the simulations with KASIMA was obtained for a simulation time according to the length of the CLaMS simulation. To quantify the differences between the simulations with CLaMS and KASIMA, and the CRISTA observations, the probability density function technique (PDF) is used to interpret the tracer distributions. While in the PDF of the KASIMA simulation the small scale structures observed by CRISTA are smoothed out due to the numerical diffusion in the model, the PDFs derived from CRISTA observations can be reproduced by CLaMS by optimising the mixing parameterisation. Further, this procedure gives information onsmall-scale variabilities not resolved by the CRISTA observations.
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| 7. |
- Krämer, Martina, et al.
(författare)
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A microphysics guide to cirrus – Part 2 : Climatologies of clouds and humidity from observations
- 2020
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:21, s. 12569-12608
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Tidskriftsartikel (refereegranskat)abstract
- This study presents airborne in situ and satellite remote sensing climatologies of cirrus clouds and humidity. The climatologies serve as a guide to the properties of cirrus clouds, with the new in situ database providing detailed insights into boreal midlatitudes and the tropics, while the satellite-borne data set offers a global overview.To this end, an extensive, quality-checked data archive, the Cirrus Guide II in situ database, is created from airborne in situ measurements during 150 flights in 24 campaigns. The archive contains meteorological parameters, ice water content (IWC), ice crystal number concentration (Nice), ice crystal mean mass radius (Rice), relative humidity with respect to ice (RHice), and water vapor mixing ratio (H2O) for each of the flights. Depending on the parameter, the database has been extended by about a factor of 5–10 compared to earlier studies.As one result of our investigation, we show that the medians of Nice, Rice, and RHice have distinct patterns in the IWC–T parameter space. Lookup tables of these variables as functions of IWC and T can be used to improve global model cirrus representation and remote sensing retrieval methods. Another outcome of our investigation is that across all latitudes, the thicker liquid-origin cirrus predominate at lower altitudes, while at higher altitudes the thinner in situ-origin cirrus prevail. Further, examination of the radiative characteristics of in situ-origin and liquid-origin cirrus shows that the in situ-origin cirrus only slightly warm the atmosphere, while liquid-origin cirrus have a strong cooling effect.An important step in completing the Cirrus Guide II is the provision of the global cirrus Nice climatology, derived by means of the retrieval algorithm DARDAR-Nice from 10 years of cirrus remote sensing observations from satellite. The in situ measurement database has been used to evaluate and improve the satellite observations. We found that the global median Nice from satellite observations is almost 2 times higher than the in situ median and increases slightly with decreasing temperature. Nice medians of the most frequently occurring cirrus sorted by geographical regions are highest in the tropics, followed by austral and boreal midlatitudes, Antarctica, and the Arctic. Since the satellite climatologies enclose the entire spatial and temporal Nice occurrence, we could deduce that half of the cirrus are located in the lowest, warmest (224–242 K) cirrus layer and contain a significant amount of liquid-origin cirrus.A specific highlight of the study is the in situ observations of cirrus and humidity in the Asian monsoon anticyclone and the comparison to the surrounding tropics. In the convectively very active Asian monsoon, peak values of Nice and IWC of 30 cm−3 and 1000 ppmv are detected around the cold point tropopause (CPT). Above the CPT, ice particles that are convectively injected can locally add a significant amount of water available for exchange with the stratosphere. We found IWCs of up to 8 ppmv in the Asian monsoon in comparison to only 2 ppmv in the surrounding tropics. Also, the highest RHice values (120 %–150 %) inside of clouds and in clear sky are observed around and above the CPT. We attribute this to the high H2O mixing ratios (typically 3–5 ppmv) observed in the Asian monsoon compared to 1.5 to 3 ppmv found in the tropics. Above the CPT, supersaturations of 10 %–20 % are observed in regions of weak convective activity and up to about 50 % in the Asian monsoon. This implies that the water available for transport into the stratosphere might be higher than the expected saturation value.
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| 8. |
- Riese, Emma, 1992-, et al.
(författare)
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Challenges Faced by Teaching Assistants in Computer Science Education Across Europe
- 2021
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Ingår i: ITiCSE 2021. - New York, NY, United States : Association for Computing Machinery (ACM). ; , s. 547-553
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Konferensbidrag (refereegranskat)abstract
- Teaching assistants (TAs) are heavily used in computer science courses as a way to handle high enrollment and still being able to offer students individual tutoring and detailed assessments. TAs are themselves students who take on this additional role in parallel with their own studies at the same institution. Previous research has shown that being a TA can be challenging but has mainly been conducted on TAs from a single institution or within a single course. This paper offers a multi-institutional, multi-national perspective of challenges that TAs in computer science face. This has been done by conducting a thematic analysis of 180 reflective essays written by TAs from three institutions across Europe. The thematic analysis resulted in five main challenges: becoming a professional TA, student focused challenges, assessment, defining and using best practice, and threats to best practice. In addition, these challenges were all identified within the essays from all three institutions, indicating that the identified challenges are not particularly context-dependent. Based on these findings, we also outline implications for educators involved in TA training and coordinators of computer science courses with TAs.
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| 9. |
- van de Vegte, Yordi, et al.
(författare)
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Genetic insights into resting heart rate and its role in cardiovascular disease
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The genetics and clinical consequences of resting heart rate (RHR) remain incompletely understood. Here, the authors discover new genetic variants associated with RHR and find that higher genetically predicted RHR decreases risk of atrial fibrillation and ischemic stroke. Resting heart rate is associated with cardiovascular diseases and mortality in observational and Mendelian randomization studies. The aims of this study are to extend the number of resting heart rate associated genetic variants and to obtain further insights in resting heart rate biology and its clinical consequences. A genome-wide meta-analysis of 100 studies in up to 835,465 individuals reveals 493 independent genetic variants in 352 loci, including 68 genetic variants outside previously identified resting heart rate associated loci. We prioritize 670 genes and in silico annotations point to their enrichment in cardiomyocytes and provide insights in their ECG signature. Two-sample Mendelian randomization analyses indicate that higher genetically predicted resting heart rate increases risk of dilated cardiomyopathy, but decreases risk of developing atrial fibrillation, ischemic stroke, and cardio-embolic stroke. We do not find evidence for a linear or non-linear genetic association between resting heart rate and all-cause mortality in contrast to our previous Mendelian randomization study. Systematic alteration of key differences between the current and previous Mendelian randomization study indicates that the most likely cause of the discrepancy between these studies arises from false positive findings in previous one-sample MR analyses caused by weak-instrument bias at lower P-value thresholds. The results extend our understanding of resting heart rate biology and give additional insights in its role in cardiovascular disease development.
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| 10. |
- Weigel, Katja, et al.
(författare)
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A stratospheric intrusion at the subtropical jet over the Mediterranean Sea : air-borne remote sensing observations and model results
- 2012
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 12:18, s. 8423-8438
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Tidskriftsartikel (refereegranskat)abstract
- Remote sensing measurements from the Cryogenic Infrared Spectrometers and Telescope for the Atmosphere – New Frontiers (CRISTA-NF) during a flight on 29 July 2006 are presented. This flight is part of the AMMA-SCOUT-O3 measurement campaign, where CRISTA-NF was deployed on the high-flying research aircraft M55-Geophysica. The flight path was located over Italy and the Mediterranean Sea and crossed over the subtropical jet twice. Measurements of temperature, and the volume mixing ratios of water vapor (H2O), ozone (O3), nitric acid (HNO3) and peroxyacetyl nitrate (PAN) are available with a vertical resolution of up to 500 m between about 6 to 21 km altitude. CRISTA-NF observes these trace gases simultaneously and provides a quasi-2-D view of the transition region between the troposphere and the stratosphere. The observation of these different trace gases allows to determine tropospheric and stratospheric air masses. As expected, higher abundances are found where the main source of the trace gases is located: in the stratosphere for O3 and in the troposphere for H2O and PAN. Tracer-tracer correlations between O3 and PAN are used to identify the mixed tropospheric and lowermost stratospheric air at the subtropical jet and around the thermal tropopause north of the jet. An intrusion of stratospheric air into the troposphere associated with the subtropical jet is found in the CRISTA-NF observations. The observations indicate that the intrusion is connected to a tropopause fold which is not resolved in the ECMWF analysis data. The intrusion was reproduced in a simulation with the Chemical Lagrangian Model of the Stratosphere (CLaMS). The CLaMS simulation shows, that the lowermost stratospheric air masses in the intrusion where transported along the the subtropical jet. The tropospheric air masses around the intrusion originate from the vicinity of the Asian monsoon anticyclone. This work discusses the nature of the observed processes at the subtropical jet based on the CRISTA-NF observations and the CLaMS simulation.
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