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Farzana Yasmin,1,* Andreas Schultz,2,3,* Ajib Phiri,2 Ralf Weigel1 1Friede Springer Endowed Professorship for Global Child Health, Witten/Herdecke University, Witten, Germany; 2Kamuzu University of Health Sciences, School of Medicine and Oral Health, Lilongwe, Malawi; 3Institute for Hygiene and Public Health, University of Bonn, Bonn, Germany*These authors contributed equally to this workCorrespondence: Farzana Yasmin, Friede Springer Endowed Professorship for Global Child Health, Witten/Herdecke University, Alfred-Herrhausen-Strasse 50, Witten, 58448, Germany, Tel +49 2302 926 796, Fax +49 2302 926 44746, Email farzana.yasmin@uni-wh.dePurpose: To improve child health care depends on the availability of sufficient numbers of skilled healthcare workers. To achieve this, the German Society of Tropical Paediatrics & International Child Health supported the existing three-year Bachelor of Science in Paediatrics and Child Health training for Clinical Officers, a non-physician clinician cadre, from 09/2017 to 08/2019. This study aims to evaluate the project to inform forthcoming training.Methods: All 17 students who were in training took part in this study. Quantitative data collection took place between 01/2018 to 06/2019 using the post-self-assessment bloc course survey, Research Self-Efficacy Scale (RSES), and Stages of Change (SOC) model. Students and key informants participated in three focus group discussions and five in-depth interviews during April 1– 10, 2019.Results: Students mostly perceived bloc course contents “At their level” (92%) and “Very important/relevant” (61%) with “Good quality” teaching (70.5%). The mean (SD) score for RSES (10-point scale) was 9.10 (0.91). The SOC (4-point scale) scores were higher for “Attitude” and “Intention” statements than “Action”. Students found the program well-paced, felt that their clinical knowledge and skills had improved, and valued the acquired holistic disease management approach. They reported increased confidence and being more prepared for leadership roles in their future work. The involvement of international teachers and supervisors enriched their global perspectives.Conclusion: Students improved their clinical and non-clinical skills, developed self-efficacy and attitudes toward research, and were confident to build and utilize their networks. These transformative experiences could facilitate the development of change agents among current and future trainees.Keywords: clinical officer, health partnership, child health, transformative learning, interdependence in education, change agent, non-physician clinician

Aircraft-borne in situ measurements of the chemical aerosol composition were conducted in the Asian tropopause aerosol layer (ATAL) over the Indian subcontinent in the summer of 2017, covering particle sizes below ∼3 µm. We have implemented a recently developed aerosol mass spectrometer, which adopts the laser desorption technique as well as the thermal desorption method for quantitative bulk information (i.e., a modified Aerodyne AMS), aboard the high-altitude research aircraft M-55 Geophysica. The instrument was deployed in July and August 2017 during the StratoClim EU campaign (Stratospheric and upper tropospheric processes for better Climate predictions) over Nepal, India, Bangladesh, and the Bay of Bengal, covering altitudes up to 20 kma.s.l. For particles with diameters between 10 nm and ∼3 µm, the vertical profiles of aerosol number densities from the eight research flights show significant enhancements in the altitude range of the ATAL. We observed enhancements in the mass concentrations of particulate nitrate, ammonium, and organics in a similar altitude range between approximately 13 and 18 km (corresponding to 360 and 410 K potential temperature). By means of the two aerosol mass spectrometry techniques, we show that the particles in the ATAL mainly consist of ammonium nitrate (AN) and organics. The single-particle analysis from laser desorption and ionization mass spectrometry revealed that a significant particle fraction (up to 70 % of all analyzed particles by number) within the ATAL results from the conversion of inorganic and organic gas-phase precursors, rather than from the uplift of primary particles from below. This can be inferred from the fact that the majority of the particles encountered in the ATAL consisted solely of secondary substances, namely an internal mixture of nitrate, ammonium, sulfate, and organic matter. These particles are externally mixed with particles containing primary components as well. The single-particle analysis suggests that the organic matter within the ATAL and in the lower stratosphere (even above 420 K) can partly be identified as organosulfates (OS), in particular glycolic acid sulfate, which are known as components indicative for secondary organic aerosol (SOA) formation. Additionally, the secondary particles are smaller in size compared to those containing primary components (mainly potassium, metals, and elemental carbon). The analysis of particulate organics with the thermal desorption method shows that the degree of oxidation for particles observed in the ATAL is consistent with expectations about secondary organics that were subject to photochemical processing and aging. We found that organic aerosol was less oxidized in lower regions of the ATAL (

Although great improvements in child survival were achieved in the past two decades, progress has been uneven within and across countries, and the COVID-19 pandemic threatens to reverse previous advances. Demographic and epidemiological transitions around the world have resulted in shifts in the causes and distribution of child death and diseases, and many children are living with short-term and long-term chronic illnesses and disabilities. These changes, plus global threats such as pandemics, transnational and national security issues, and climate change, mean that regular monitoring of child health and wellbeing is essential if we are to achieve the Sustainable Development Goals. This Health Policy describes the three-phased process undertaken by the Child Health Accountability Tracking technical advisory group (CHAT) to develop a core set of indicators on child health and wellbeing for global monitoring purposes, and presents CHAT's research recommendations to address data gaps. CHAT reached consensus on 20 core indicators specific to the health sector, which include 11 impact-level indicators and nine outcome-level indicators that cover the topics of: acute conditions and prevention; health promotion and child development; and chronic conditions, disabilities, injuries, and violence against children. An additional six indicators (three impact and three outcome) that capture information on child health issues such as malaria and HIV are recommended; however, these indicators are only relevant to high-burden regions. CHAT's four research priorities will require investments in health information systems and measurement activities. These investments will help to increase data on children aged 5-9 years; develop standard metadata and data collection processes to enable cross-country comparisons and progress assessments over time; reach a global consensus on essential interventions and associated indicators for monitoring emerging priority areas such as child development, chronic conditions, disabilities, and injuries; and implement strategies to increase the uptake of data on child health to improve evidence-based planning, programming, and advocacy efforts.

We analyze cirrus cloud measurements from two dual-instrument cloud spectrometers, two hygrometers and a backscattersonde in view to connect cirrus optical parameters usually accessible by remote sensing with microphysical size resolved and bulk properties accessible in situ. Specifically, we compare the particle backscattering coefficient and depolarization ratio to the particle size distribution, effective and mean radius, surface area density, particle aspherical fraction and ice water content. Data have been acquired by instruments on board the M55 Geophysica research aircraft during July and August 2017 during the Asian Monsoon campaign based in Kathmandu, Nepal, in the framework of the StratoClim (Stratospheric and upper tropospheric processes for better climate predictions) project. Cirrus have been observed over the Hymalaian region between 10 km and the tropopause, situated at 17–18 km. The observed particle number densities varied between 10 and 10-4 cm-3 in the dimensional range from 1.5 to 468.5 μm in radius. Correspondingly, backscatter ratios from one tenth up to 50 have been observed. Optical scattering theory has been used to compare the backscattering coefficient computed from measured particle size distribution with those directly observed by the backscattersonde. The aspect ratio of the particles, modeled as spheroids for the T-matrix approach, was left as a free parameter to match the calculations to the optical measures. The computed backscattering coefficient can be set in good agreement with the observed one, but the match between simulated and determined depolarization ratios is insufficient, however. Relationships between ice particle concentration, mean and effective radius, surface area density and ice water content with the measured backscattering coefficient are investigated for an estimate of the bulk microphysical parameters of cirrus clouds from remote sensing lidar data. The comparison between particle depolarization and aspherical fraction as measured by one of the cloud spectrometers equipped with a detector for polarization, represents a novelty since it was the first time the two instruments are operated simultaneously on aircraft. The analysis shows the difficulty of establishing an univocal link between depolarization values and the presence and amount of aspherical scatterers. This suggests the need of further investigation that could take into consideration not only the fraction of aspheric particles but also their predominant morphology.

Satellite- and aircraft-based mid-infrared measurements of polar stratospheric clouds (PSCs) have provided spectroscopic evidence for the presence of β-NAT (nitric acid trihydrate) particles. Metastable nitric acid hydrate phases such as α-NAT and α-NAD (nitric acid dihydrate) have been frequently observed in laboratory experiments, but not yet detected as a constituent of PSCs in atmospheric measurements. As for the β-NAD modification, its formation was first observed in X-ray diffraction measurements when the low-temperature α-NAD phase was warmed to a temperature above 210 K. Its infrared spectrum has been reported, but so far no optical constants have been derived that could be used as input for infrared retrievals of PSC composition. In this work, we show that β-NAD particles were efficiently formed in isothermal, heterogeneous crystallisation experiments at 190 K from supercooled HNO3/H2O solution droplets containing an embedded mineral dust or meteoric smoke particle analogue. An inversion algorithm based on a T-matrix optical model was used to derive for the first time the mid-infrared complex refractive indices of the β-NAD modification from the measured extinction spectrum of the particles. In contrast to the heterogeneous crystallisation experiments, the α-NAD phase was formed when the HNO3/H2O solution droplets did not contain a solid nucleus and crystallised homogeneously. Using a light scattering detector that recorded two-dimensional scattering patterns of the crystallised NAD particles, we were able to determine predominant shapes of the α- and β-NAD crystals. We found that α-NAD grew into elongated, needle-shaped crystals, while β-NAD particles were compact in shape. This agrees with previously reported images of α- and β-NAD particles grown on the cryo-stage of an Environmental Scanning Electron Microscope.

The Asian summer monsoon is an effective pathway for aerosol particles and precursors from the planetary boundary layer over Central, South, and East Asia into the upper troposphere and lower stratosphere. An enhancement of aerosol particles within the Asian monsoon anticyclone (AMA), called the Asian tropopause aerosol layer (ATAL), has been observed by satellites. We discuss airborne in situ and remote sensing observations of aerosol microphysical properties conducted during the 2017 StratoClim field campaign within the AMA region. The aerosol particle measurements aboard the high-altitude research aircraft M55 Geophysica (maximum altitude reached of ∼20.5 km) were conducted with a modified ultra-high-sensitivity aerosol spectrometer – airborne (UHSAS-A; particle diameter detection range of 65 nm to 1 µm), the COndensation PArticle counting System (COPAS, detecting total concentrations of submicrometer-sized particles), and the New Ice eXpEriment – Cloud and Aerosol Spectrometer with Detection of POLarization (NIXE-CAS-DPOL). In the COPAS and UHSAS-A vertical particle mixing ratio (PMR) profiles and the size distribution profiles (for number, surface area, and volume concentration), the ATAL is evident as a distinct layer between ∼370 and 420 K potential temperature (Θ). Within the ATAL, the maximum detected PMRs (from the median profiles) were ∼700 mg−1 for particle diameters between 65 nm and 1 µm (UHSAS-A) and higher than 2500 mg−1 for diameters larger than 10 nm (COPAS). These values are up to 2 times higher than those previously found at similar altitudes in other tropical locations. The difference between the PMR profiles measured by the UHSAS-A and the COPAS indicate that the region below the ATAL at Θ levels from 350 to 370 K is influenced by the nucleation of aerosol particles (diameter nm). We provide detailed analyses of the vertical distribution of the aerosol particle size distributions and the PMR and compare these with previous tropical and extratropical measurements. The backscatter ratio (BR) was calculated based on the aerosol particle size distributions measured in situ. The resulting data set was compared with the vertical profiles of the BR detected by the multiwavelength aerosol scatterometer (MAS) and an airborne miniature aerosol lidar (MAL) aboard the M55 Geophysica and by the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The data of all four methods largely agree with one another, showing enhanced BR values in the altitude range of the ATAL (between ∼15 and 18.5 km) with a maximum at 17.5 km altitude. By means of the AMA-centered equivalent latitude calculated from meteorological reanalysis data, it is shown that such enhanced values of the BR larger than 1.1 could only be observed within the confinement of the AMA.

Chronic subdural hematoma (CSH) affects mostly elderly subjects. Previously, pathophysiological concepts suggested that CSH is secondary to degradation of subdural collections of blood and its products exerting merely a mass effect on the underlying brain. During the last decades, however, new insights into the pathogenetic mechanisms urge us to reconsider such a simplistic view. Here, we critically review novel pathophysiological, imaging, interventional, and medical treatment aspects and establish an integrative concept of the pathogenesis of CSH stressing the role of age as key factor. Trauma is considered a trigger event that unleashes a cascade of immunological and angiogenic age-dependent responses. These are associated with hypervascularization of the outer hematoma membrane, rebleeding, and exsudation which are crucial determinants for further development and propagation of CSH. Neurosurgical evacuation of the hematoma has long been thought the only viable treatment option, and it is still the method of choice in the majority of cases. Only more recently, embolization of the middle meningeal artery has been introduced as an alternative to surgery, and pharmacological treatment options are being investigated. Persons with advanced age trauma and other trigger events encounter a repair system with characteristics of senescence. This repair system implies a dysfunctional secretory phenotype of senescent cells and results in an insufficient repair process including chronic inflammation and fibrosis. Increased knowledge about the pathomechanisms of CSH will inform future studies and open new perspectives for its treatment and possibly also for its prevention.

We report on the developments that enabled the field deployment of a fully-automated aerosol mass spectrometer, specially designed for high-altitude measurements on unpressurised aircraft. The merits of the two main categories of real-time aerosol mass spectrometry, i.e. (a) single particle laser desorption and ionization, and (b) continuous thermal desorption / electron impact ionization of aerosols, have been integrated into one compact apparatus with the aim to perform in-situ real-time analysis of aerosol chemical composition. The demonstrated instrument, named ERICA (European Research council Instrument for the Chemical composition of Aerosols), operated successfully aboard the high-altitude research aircraft M-55 Geophysica at altitudes up to 20 km, while being exposed to ambient conditions of very low atmospheric pressure and temperature. A primary goal of those field deployments was the in-situ study of the Asian Tropopause Aerosol Layer (ATAL). During 11 research flights, the instrument operated for more than 49 hours and collected chemical composition information of more than 150,000 single particles combined with quantitative chemical composition analysis of aerosol particle ensembles. This paper presents in detail the technical characteristics of the main constituent parts of the instrument, as well as the design considerations for its integration into the aircraft and its autonomous operation in the upper troposphere and lower stratosphere (UT/LS). Additionally, system performance data from the first field deployments of the instrument are presented and discussed, together with exemplary mass spectrometry data collected during those flights.

Background International medical electives (IMEs) are entry points to global health opportunities. IME uptake at German universities is unclear. We analyse 14 y of IME. Methods Student registry data were collected. Univariate linear regression examined relationships between enrolment year and IMEs. Results The median (IQR) number of IMEs of all enrolment years was 54 (32–80) and 51 (38–67)% of all students took an IME. Enrolment year significantly predicted IME frequency and the proportion of students taking IMEs. Conclusions Student interest in IMEs is increasing. Universities should invest more broadly in IME opportunities for student, faculty and university enrichment.

Background Recommendations to prevent morbidity and mortality in children was a high priority for the editorial group of a WHO pocket book for primary health care in the European region. However, the benefit of preventive interventions is not always clear and recommendations differ across countries and institutions. Here, we summarize the existing recommendations and the most recent evidence on ten selected preventive interventions applied to children under five years to inform this group. In addition, we reflect on the process and challenges of developing these summaries. Methods For each intervention, we systematically searched for current recommendations from the WHO, the United States Preventive Services Task Force, the workgroup PrevInfad from the Spanish Association of Primary Care Pediatrics, the Centers of Disease Control and Prevention, and the National Institute for Health and Care Excellence. Then, we systematically searched the sources above and the Cochrane library for relevant systematic reviews. For each topic, we reported the recommendations and the strength of the recommendation when and as reported by the authors. We summarized the main findings of systematic reviews with the certainty of the evidence as reported. Categorising the ten preventive interventions in three groups allowed narrative comparisons between similar types of interventions and between groups. Results and discussion For the single interventions of providing vitamins D and K and topical fluoride there is overall a high degree of consensus between institutions for the evidence of their effectiveness. For the multiple interventions to prevent sudden infant death syndrome and unintentional injuries consensus was more variable as evidence of effectiveness is harder to ascertain. For the screening interventions the summaries of recommendations and evidence varied too. While institutions generally agreed in recommending for vision screening and against universal screening for language and speech delay and iron deficiency, they had some differences for pulse oximetry and autism. The transparent and independent process shed light upon how institutions use existing evidence in their settings – common and different positions were accounted for and became visible. We also identified gaps and duplications of research. Our approach was a crucial starting point for developing the respective sections in the pocket book.

Essential health, education and other service disruptions arising from the COVID-19 pandemic risk reversing some of the hard-won gains in improving child survival over the past 40 years. Although children have milder symptoms of COVID-19 disease than adults, pandemic control measures in many countries have disrupted health, education and other services for children, often leaving them without access to birth and postnatal care, vaccinations and early childhood preventive and treatment services. These disruptions mean that the SARS-CoV-2 virus, along with climate change and shifting epidemiological and demographic patterns, are challenging the survival gains that we have seen over the past 40 years. We revisit the initiatives and actions of the past that catalyzed survival improvements in an effort to learn how to maintain these gains even in the face of today’s global challenges.

The potential temperature is a widely used quantity in atmospheric science since it corresponds to the entropy and is conserved for adiabatic changes of dry air. As such, it is routinely employed in applications ranging from atmospheric dynamics to transport modeling. The common formula to compute the potential temperature is based on the assumption of a constant specific heat capacity for the dry air, even though the latter is known to vary with temperature. We re-derive the (dry air) potential temperature for a recent temperature-dependent formulation of the specific heat capacity of dry air. The result is expected to provide values which are much closer at the true entropy value (expressed as a temperature) and hence serves as the reference potential temperature. However, its computation is less straightforward compared to the classical one, motivating the development of efficient approximations. Moreover, similarities and differences are discussed between the newly derived reference potential temperature and the classical one based on a constant specific heat capacity. The new reference shows different values and vertical gradients, in particular in the stratosphere and above. Applications of the new reference potential temperature are discussed in the context of common computations in the atmospheric sciences, including the potential vorticity or diabatic heating rates.

Meteoric smoke particles (MSPs) provide a steady source of condensation nuclei to the Arctic lower stratosphere, with heterogeneous nucleation to sulphuric acid aerosol particles. Internally mixed meteoric-sulphuric particles likely also play a significant role in the formation of polar stratospheric clouds and thereby influence stratospheric ozone depletion chemistry, particularly in the quiescent stratosphere.In several Arctic winter field campaigns (EUPLEX 2002/3, RECONCILE 2009/10, ESSenCe 2010/11), in-situ stratospheric aerosol particle concentrations measurements were made from the high-altitude Geophysica aircraft, the COPAS instrument measuring total and refractory (non-volatile) particle concentrations at 20 km altitude (see Curtius et al., 2003; Weigel et al., 2014). These measurements are consistent with there being a substantial seasonal source of meteoric-sulphuric particles to the lower Arctic stratosphere, from each year’s influx of MSPs within the winter-time Arctic polar vortex. In this study we investigate the effect of MSPs on the quiescent Junge layer particle concentration as the polar vortex builds up and after it dissipates. We use the nudged configuration of the UM-UKCA stratosphere-troposphere composition-climate model to reproduce the vertical profile of stratospheric particles measured in-situ during the COPAS 2003 campaign. Our model simulates two types of stratospheric aerosol particles - pure sulphuric acid particles and sulphuric acid particles with a MSP-core. We show that the model is able to reproduce the vertical profile of aerosol particles observed during the COPAS measurements in winter 2003.Our findings illustrate the influx of MSP and SO2 from higher altitudes through the polar vortex, the winter-time build-up of SO2 triggering homogeneous nucleation of pure sulphuric particles, also with the seasonal source of MSP-core sulphuric particles nucleated heterogeneously. We assess the effects of MSPs on the quiescent period particle concentration in the Arctic during winter through to spring.

The chemistry climate model EMAC with interactive stratospheric and tropospheric aerosol is used for transient simulation of aerosol radiative forcing including effects of about 500 explosive volcanic eruptions and desert dust. We demonstrate that volcanic SO2 injections are needed to explain the StratoClim aircraft observations in August 2017 of SO2 and aerosol properties in the UTLS. This presentation includes studies to ISAMIP concerning aerosol optical depth at different wavelengths and contribution of different aerosol types, involving also multi-instrument satellite observations. We demonstrate that sulfate accumulation from consecutive smaller tropical and subtropical eruptions matters for radiative forcing, as for example in 2016.

The Asian summer monsoon is an effective pathway for aerosol particles and precursor substances from the planetary boundary layer over Central, South, and East Asia into the upper troposphere and lower stratosphere. An enhancement of aerosol particles within the Asian monsoon anticyclone (AMA) has been observed by satellites, called the Asian Tropopause Aerosol Layer (ATAL). In this paper we discuss airborne in situ and remote sensing observations of aerosol microphysical properties conducted during the 2017 StratoClim field campaign within the region of the Asian monsoon anticyclone. The aerosol particle measurements aboard the high-altitude research aircraft M55 Geophysica (reached a maximum altitude of about 20.5 km) were conducted by a modified Ultra High Sensitivity Aerosol Spectrometer Airborne (UHSAS-A; particle diameter detection range from 65 nm to 1 µm), the COndensation PArticle counting System (COPAS, for detecting total aerosol densities of submicrometer sized particles), and the Cloud and Aerosol Spectrometer with Detection of POLarization (NIXE-CAS-DPOL). In the COPAS and UHSAS-A vertical particle mixing ratio profiles, the ATAL is evident as a distinct layer between 15 km (≈ 370 K) and 18.5 km altitude (≈ 420 K potential temperature). Within the ATAL, the maximum detected particle mixing ratios (from the median profiles) were 700 mg−1 for diameters between 65 nm to 1 µm (UHSAS-A) and higher than 2500 mg−1 for diameters larger than 10 nm (COPAS). These values are up to two times higher than previously found at similar altitudes in other tropical locations. The difference between the particle mixing ratio profiles measured by the UHSAS-A and the COPAS indicate that the region below the ATAL at potential temperatures from 350 to 370 K is influenced by the fresh nucleation of aerosol particles (diameter

We analyse aerosol particle composition measurements from five research missions between 2014 and 2018 to assess the meridional extent of particles containing meteoric material in the upper troposphere and lower stratosphere (UTLS). Measurements from the Jungfraujoch mountaintop site and a low-altitude aircraft mission show that meteoric material is also present within middle- and lower-tropospheric aerosol but within only a very small proportion of particles. For both the UTLS campaigns and the lower- and mid-troposphere observations, the measurements were conducted with single-particle laser ablation mass spectrometers with bipolar-ion detection, which enabled us to measure the chemical composition of particles in a diameter range of approximately 150 nm to 3 µm. The five UTLS aircraft missions cover a latitude range from 15 to 68∘ N, altitudes up to 21 km, and a potential temperature range from 280 to 480 K. In total, 338 363 single particles were analysed, of which 147 338 were measured in the stratosphere. Of these total particles, 50 688 were characterized by high abundances of magnesium and iron, together with sulfuric ions, the vast majority (48 610) in the stratosphere, and are interpreted as meteoric material immersed or dissolved within sulfuric acid. It must be noted that the relative abundance of such meteoric particles may be overestimated by about 10 % to 30 % due to the presence of pure sulfuric acid particles in the stratosphere which are not detected by the instruments used here. Below the tropopause, the observed fraction of the meteoric particle type decreased sharply with 0.2 %–1 % abundance at Jungfraujoch, and smaller abundances (0.025 %–0.05 %) were observed during the lower-altitude Canadian Arctic aircraft measurements. The size distribution of the meteoric sulfuric particles measured in the UTLS campaigns is consistent with earlier aircraft-based mass-spectrometric measurements, with only 5 %–10 % fractions in the smallest particles detected (200–300 nm diameter) but with substantial (> 40 %) abundance fractions for particles from 300–350 up to 900 nm in diameter, suggesting sedimentation is the primary loss mechanism. In the tropical lower stratosphere, only a small fraction (< 10 %) of the analysed particles contained meteoric material. In contrast, in the extratropics the observed fraction of meteoric particles reached 20 %–40 % directly above the tropopause. At potential temperature levels of more than 40 K above the thermal tropopause, particles containing meteoric material were observed in much higher relative abundances than near the tropopause, and, at these altitudes, they occurred at a similar abundance fraction across all latitudes and seasons measured. Above 440 K, the observed fraction of meteoric particles is above 60 % at latitudes between 20 and 42∘ N. Meteoric smoke particles are transported from the mesosphere into the stratosphere within the winter polar vortex and are subsequently distributed towards low latitudes by isentropic mixing, typically below a potential temperature of 440 K. By contrast, the findings from the UTLS measurements show that meteoric material is found in stratospheric aerosol particles at all latitudes and seasons, which suggests that either isentropic mixing is effective also above 440 K or that meteoric fragments may be the source of a substantial proportion of the observed meteoric material.

From 27 July to 10 August 2017 the airborne StratoClim mission took place in Kathmandu, Nepal where eight mission flights were conducted with the M-55 Geophysica up to altitudes of 20 km. New Particle Formation (NPF) was identified by the abundant presence of ultrafine aerosols, with particle diameters dp smaller than 15 nm, which were in-situ detected by means of condensation nuclei counting techniques. NPF fields in clear-skies as well as in the presence of cloud ice particles (dp > 3 µm) were encountered at upper troposphere/lowermost stratosphere (UT/LS) levels and within the Asian Monsoon Anticyclone (AMA). NPF-generated ultrafine particles in elevated concentrations (Nuf) were frequently found together with cloud ice (in number concentrations Nice of up to 3 cm−3) at heights between ~ 11 km and 16 km. From a total measurement time of ~ 22.5 hours above 10 km altitude, in-cloud NPF was in sum detected over ~ 1.3 hours (~ 50 % of all NPF records throughout StratoClim). Maximum Nuf of up to ~ 11000 cm−3 were detected coincidently with intermediate ice particle concentrations Nice of 0.05–0.1 cm−3 at comparatively moderate carbon monoxide (CO) contents of ~ 90–100 nmol mol−1. Neither under clear-sky nor during in-cloud NPF do the highest Nuf concentrations correlate with the highest CO mixing ratios, suggesting that an elevated pollutant load is not a prerequisite for NPF. Under clear-air conditions, NPF with elevated Nuf (> 8000 cm−3) occurred slightly less often than within clouds. In the presence of cloud ice, NPF with Nuf between 1500–4000 cm−3 were observed about twice as often as under clear air conditions. When ice water contents exceeded 1000 µmol mol−1 in very cold air ( 5000 mg−1) were rarely observed (~ 6 % of in-cloud NPF data). For specifying the constraining mechanisms for NPF possibly imposed by the microphysical properties of the cloud elements, the integral radius (IR) of the ice cloud population was identified as the most practicable indicator. Neither of both, the number of ice particles or the free distance between the ice particles, is clearly related to the NPF-rate detected. The results of a numerical simulation indicates how the IR affects the supersaturation of a condensable vapour, such as sulphuric acid, and that IR determines the effective limitation of NPF rates due to cloud ice.

During the monsoon season of the year 2017 the airborne StratoClim mission took place in Kathmandu, Nepal with eight mission flights of the M-55 Geophysica in the upper troposphere/lower stratosphere (UT/LS) of the Asian Monsoon Anticyclone (AMA) over northern India, Nepal and Bangladesh. More than hundred events of New Particle Formation (NPF) were observed. In total, more than two hours of flight time were spent under NPF conditions as indicated by the abundant presence of ultrafine aerosols, i.e. with particle diameters dp smaller than 15 nm, which were in-situ detected by means of condensation nuclei counting techniques. Mixing ratios of ultrafine particles (nuf) of up to ~ 50000 mg−1 were measured at heights of 15–16 km (θ ≈ 370 K). NPF was most frequently observed at ~ 12–16 km altitude (θ ≈ 355–380 K) and mainly below the tropopause , but nuf remained elevated (~ 300–2000 mg−1) up to altitudes of ~ 17.5 km (θ ≈ 400 K) while under NPF conditions the fraction (f) of submicrometre-sized non-volatile particle residues (dp > 10 nm) remained below 50 %. At ~ 12–14 km (θ ≈ 355–365 K) the minimum of f (

In this paper we analyze aerosol particle composition measurements from five research missions conducted between 2014 and 2018 sampling the upper troposphere and lower stratosphere (UTLS), to assess the meridional extent of particles containing meteoric material. Additional data sets from a ground based study and from a low altitude aircraft mission are used to confirm the existence of meteoric material in lower tropospheric particles. Single particle laser ablation techniques with bipolar ion detection were used to measure the chemical composition of particles in a size range of approximately 150 nm to 3 μm. The five UTLS aircraft missions cover a latitude range from 15 to 68° N, altitudes up to 21 km, and a potential temperature range from 280 to 480 K. In total, 338 363 single particles were analyzed, of which 147 338 particles were measured in the stratosphere. Of these particles, 50 688 were characterized by high abundances of magnesium, iron, and rare iron oxide compounds, together with sulfuric acid. This particle type was found almost exclusively in the stratosphere (48 610 particles) and is interpreted as meteoric material immersed or dissolved within stratospheric sulfuric acid particles. Below the tropopause, the observed fraction of this particle type decreases sharply. However, small fractional abundances were observed below 3000 m a.s.l. in the Canadian Arctic and also at the Jungfraujoch high altitude station (3600 m a.s.l.). Thus, the removal pathway by sedimentation and/or mixing into the troposphere is confirmed. In the tropical lower stratosphere, only a small fraction (

Background: Malawi has a critical shortage of skilled health workers limiting its ability to achieve its outlined national health goals. To address this, in 2012, theMinistry of Health and the College of Medicine introduced a three-year specialist Bachelor of Science (BSc) degree in Paediatric and Child Health (PCH) for Clinical Officers, a non-physician clinician cadre. In this training program, learning occurs through supervised ward rounds, bloc courses, and a research project. The German Society of Paediatrics and International Child Health, with funding from the German government, provided support between 09/2017 and 08/2019. This study aims to evaluate this support project to model the training for the coming cohorts of BSc PCHCO students.Methods:All 17 currently enrolled students took partin this study. Quantitative data was collected between 01/2018 using the Research Self-Efficacy Scale (RSES, ten-point scale), Stages of Change (SOC, four-point scale), and the post-self-assessment survey of bloc courses (five-point scale). In addition, three focus group discussions and five in-depth interviews with students and key informants were conductedduring April 1-10, 2019.Results:The mean (SD) scores for RSES and SOC model were 9.10 (0.91) and 3.54 (0.40) respectively; for the bloc course post-self-assessment it was 3.26 (0.48). Students found the program well-paced, felt that their clinical knowledge and skills had improved, and valued the acquired holistic approach of disease management which included the social determinants of health. They reported increased confidence and being more prepared for leadership roles at their facility and community. The involvement of international lecturers enriched their global perspectives. Students had concerns about theirrecognition in the government system and continued support after graduation. The shortage ofsupervising and teaching staff was perceived as a key barrier to continuing the program. Conclusion: Studentsimproved theirclinical expertise, developed self-efficacy, andnew attitudes towards research. Application of various educational strategies through this project and the involvement of teachers from diverse backgrounds may enable them to build their professional networks. Continuous professional development and alumni mentoring are recommended to sustain the achieved results.

During the StratoClim 2017 measurement campaign in Nepal, within the Asian Monsoon Anticyclone (AMA), measurements of the aerosols’ microphysical properties up to UT/LS altitudes were successfully completed with a modified version of the commercially available (Droplet Measurement Technologies Inc.) aerosol spectrometer UHSAS-A. Technical rearrangements of parts of the UHSAS-A were developed and implemented, which improve the instrument’s measuring performance and extend its airborne application range from around 12 km altitude to the extreme ambient conditions in the stratosphere at heights of 20 km. The measurement techniques used for this purpose were characterized by laboratory experiments.Within the AMA region, extreme values of the particle mixing ratio (PMR) ranging between 6 mg-1 and about 10000 mg-1 were found with the UHSAS-A (particle diameter range: 65 nm to 1000 nm). The median of the PMR for all research flights was about 1300 mg-1 close to the ground. Within tropospheric altitudes, the PMR was highly variable and median values between 70 mg-1 and 400 mg-1 were observed. At levels of 370 K potential temperature, the median PMR maximally reaches about 700 mg-1 while the 1 Hz resolved measurements show values up to about 10000 mg-1. Between 450 K and 475 K, median PMR between 40 mg-1 and 50 mg-1 were observed. The aerosol size distributions (measured by the UHSAS-A) were extended by an additional diameter size bin obtained from the 4-channel Condensation Particle counting System (COPAS), i.e. for aerosol diameter between 10 nm and 65 nm.The UHSAS-A measured aerosol particle size distributions were compared with balloon-borne measurements (by T. Deshler et al., Dep. of Atmospheric Science, University of Wyoming, USA) at altitudes of up to 20 km. These show that the size distributions measured during the StratoClim 2017 campaign fit well within the range of the balloon-borne measurements during the Asian Monsoon season over India (Hyderabad) in 2015 and the USA (Laramie) in 2013. Further analyses of measured particle size distributions by means of backscatter ratio show remarkable consistency with CALIOP satellite observations of the ATAL during the StratoClim mission period.

Results from a transient 28 year simulation with the chemistry climate model EMAC with interactive modal aerosol scheme nudged to observed tropospheric meteorology (ERA-Interim) which includes about 500 volcanic SO2 injections are compared with in situ aircraft observations in the UT/LS in the Asian Monsoon anticyclone. Enhanced SO2 observed by STRATOMAS and enhanced sulfate aerosol observed by ERICA in the LS point to impact of several explosive eruptions of the Indonesian volcano Sinabung during summer 2017 seen by the OSIRIS satellite instrument. This is supported by freshly nucleated particles observed by COPAS in the UTLS. We present several sensitivity studies with EMAC with different assumptions on the injection patterns in comparison to the observations in July/August 2017. The monsoon dynamics distributes the volcanic material together with Asian pollution into the global lower stratosphere.

Solar radiation reflected by cirrus and deep convective clouds (DCCs) was measured by the Spectral Modular Airborne Radiation Measurement System (SMART) installed on the German High Altitude and Long Range Research Aircraft (HALO) during the Mid-Latitude Cirrus (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interaction and Dynamic of Convective Clouds System – Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modelling and to the Global Precipitation Measurement (ACRIDICON-CHUVA) campaigns. On particular flights, HALO performed measurements closely collocated with overpasses of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite. A cirrus cloud located above liquid water clouds and a DCC topped by an anvil cirrus are analyzed in this paper. Based on the nadir spectral upward radiance measured above the two clouds, the optical thickness τ and particle effective radius reff of the cirrus and DCC are retrieved using a radiance ratio technique, which considers the cloud thermodynamic phase, the vertical profile of cloud microphysical properties, the presence of multilayer clouds, and the heterogeneity of the surface albedo. For the cirrus case, the comparison of τ and reff retrieved on the basis of SMART and MODIS measurements yields a normalized mean absolute deviation of up to 1.2 % for τ and 2.1 % for reff. For the DCC case, deviations of up to 3.6 % for τ and 6.2 % for reff are obtained. The larger deviations in the DCC case are mainly attributed to the fast cloud evolution and three-dimensional (3-D) radiative effects. Measurements of spectral upward radiance at near-infrared wavelengths are employed to investigate the vertical profile of reff in the cirrus. The retrieved values of reff are compared with corresponding in situ measurements using a vertical weighting method. Compared to the MODIS observations, measurements of SMART provide more information on the vertical distribution of particle sizes, which allow reconstructing the profile of reff close to the cloud top. The comparison between retrieved and in situ reff yields a normalized mean absolute deviation, which ranges between 1.5 and 10.3 %, and a robust correlation coefficient of 0.82.

We have investigated how aerosols affect the height above cloud base of rain and ice hydrometeor initiation and the subsequent vertical evolution of cloud droplet size and number concentrations in growing convective cumulus. For this purpose we used in situ data of hydrometeor size distributions measured with instruments mounted on HALO aircraft during the ACRIDICON–CHUVA campaign over the Amazon during September 2014. The results show that the height of rain initiation by collision and coalescence processes (Dr, in units of meters above cloud base) is linearly correlated with the number concentration of droplets (Nd in cm−3) nucleated at cloud base (Dr ≈ 5 ⋅ Nd). Additional cloud processes associated with Dr, such as GCCN, cloud, and mixing with ambient air and other processes, produce deviations of ∼ 21 % in the linear relationship, but it does not mask the clear relationship between Dr and Nd, which was also found at different regions around the globe (e.g., Israel and India). When Nd exceeded values of about 1000 cm−3, Dr became greater than 5000 m, and the first observed precipitation particles were ice hydrometeors. Therefore, no liquid water raindrops were observed within growing convective cumulus during polluted conditions. Furthermore, the formation of ice particles also took place at higher altitudes in the clouds in polluted conditions because the resulting smaller cloud droplets froze at colder temperatures compared to the larger drops in the unpolluted cases. The measured vertical profiles of droplet effective radius (re) were close to those estimated by assuming adiabatic conditions (rea), supporting the hypothesis that the entrainment and mixing of air into convective clouds is nearly inhomogeneous. Additional CCN activation on aerosol particles from biomass burning and air pollution reduced re below rea, which further inhibited the formation of raindrops and ice particles and resulted in even higher altitudes for rain and ice initiation.

Clouds have a crucial impact on the energy balance of the Earth-Atmosphere system. They can cool the system by partly reflecting or scattering of the incoming solar radiation (albedo effect); moreover, thermal radiation as emitted from the Earth's surface can be absorbed and partly re-emitted by clouds leading to a warming of the atmosphere (greenhouse effect). The effectiveness of both effects crucially depends on the size and the shape of a cloud's particulate constituents, i.e. liquid water droplets or solid ice crystals. For studying cloud microphysics, in situ measurements on board of aircraft are commonly used. An important class of measurement techniques comprises optical array probes (OAPs) as developed since the 1970s [13] . While water droplets can be assumed as spherical, the shape and size of ice particles are highly variable. The currently used analysis methods to determine the particles’ size from OAP detection do rarely consider shape details or fine structures of ice particles, which may lead to artificial biases in the results. In this paper, we present two new computational analysis methods, combined in an hybrid approach, for an automatic classification of ice particles and water droplets. The first method computes the principal components of a cloud particle and uses them to determine an ellipse, which can then be used to filter for spherical particles. The second method uses convolutional neural networks (CNNs) for the classification of columns and rosettes, respectively. Although we currently only classify these two particle types with CNNs, the presented method can be easily adapted for the classification of other particle types. The particularity of our method is that we use a virtual data set to pre-train the networks, which are then further trained with a smaller amount of manually classified real cloud particles in a fine tuning step. We evaluated our models on a small data set of real cloud particles and in a final field test on OAP image data that was not previously classified. The precision of this field test was better than 81% and ranged up to 98%, demonstrating that the new methods are suitable for providing profound shape classifications of cloud particle images obtained by OAP measurements. All methods we describe in this paper have been implemented in Python and C and are fully open source. Code and documentation are available on Github ( https://github.com/lcsgrlch/oap ).

Introduction: The treatment of neuropathic and central pain still remains a major challenge. Thalamic deep brain stimulation (DBS) involving various target structures is a therapeutic option which has received increased re-interest. Beneficial results have been reported in several more recent smaller studies, however, there is a lack of prospective studies on larger series providing long term outcomes. Methods: Forty patients with refractory neuropathic and central pain syndromes underwent stereotactic bifocal implantation of DBS electrodes in the centromedian–parafascicular (CM–Pf) and the ventroposterolateral (VPL) or ventroposteromedial (VPM) nucleus contralateral to the side of pain. Electrodes were externalized for test stimulation for several days. Outcome was assessed with five specific VAS pain scores (maximum, minimum, average pain, pain at presentation, allodynia). Results: The mean age at surgery was 53.5 years, and the mean duration of pain was 8.2 years. During test stimulation significant reductions of all five pain scores was achieved with either CM–Pf or VPL/VPM stimulation. Pacemakers were implanted in 33/40 patients for chronic stimulation for whom a mean follow-up of 62.8 months (range 3–180 months) was available. Of these, 18 patients had a follow-up beyond four years. Hardware related complications requiring secondary surgeries occurred in 11/33 patients. The VAS maximum pain score was improved by ≥50% in 8/18, and by ≥30% in 11/18 on long term follow-up beyond four years, and the VAS average pain score by ≥50% in 10/18, and by ≥30% in 16/18. On a group level, changes in pain scores remained statistically significant over time, however, there was no difference when comparing the efficacy of CM–Pf versus VPL/VPM stimulation. The best results were achieved in patients with facial pain, poststroke/central pain (except thalamic pain), or brachial plexus injury, while patients with thalamic lesions had the least benefit. Conclusion: Thalamic DBS is a useful treatment option in selected patients with severe and medically refractory pain.

The Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, and climate impact of natural cirrus and aircraft-induced contrail cirrus. Direct observations of cirrus properties and their variability are still incomplete, currently limiting our understanding of the clouds’ impact on climate. Also, dynamical effects on clouds and feedbacks are not adequately represented in today’s weather prediction models. Here, we present the rationale, objectives, and selected scientific highlights of ML-CIRRUS using the G-550 aircraft of the German atmospheric science community. The first combined in situ–remote sensing cloud mission with HALO united state-of-the-art cloud probes, a lidar and novel ice residual, aerosol, trace gas, and radiation instrumentation. The aircraft observations were accompanied by remote sensing from satellite and ground and by numerical simulations. In spring 2014, HALO performed 16 flights above Europe with a focus on anthropogenic contrail cirrus and midlatitude cirrus induced by frontal systems including warm conveyor belts and other dynamical regimes (jet streams, mountain waves, and convection). Highlights from ML-CIRRUS include 1) new observations of microphysical and radiative cirrus properties and their variability in meteorological regimes typical for midlatitudes, 2) insights into occurrence of in situ–formed and lifted liquid-origin cirrus, 3) validation of cloud forecasts and satellite products, 4) assessment of contrail predictability, and 5) direct observations of contrail cirrus and their distinction from natural cirrus. Hence, ML-CIRRUS provides a comprehensive dataset on cirrus in the densely populated European midlatitudes with the scope to enhance our understanding of cirrus clouds and their role for climate and weather.