19 research outputs found

    Record high solar irradiance in Western Europe during first COVID-19 lockdown largely due to unusual weather

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    Spring 2020 broke sunshine duration records across western Europe. The Netherlands recorded the highest surface irradiance since 1928, exceeding the previous extreme of 2011 by 13 %, and the diffuse fraction of the irradiance measured a record low percentage (38 %). The coinciding irradiance extreme and a reduction in anthropogenic pollution due to COVID-19 measures triggered the hypothesis that cleaner-than-usual air contributed to the record. Based on analyses of ground-based and satellite observations and experiments with a radiative transfer model, we estimate a 1.3 % (2.3 W māˆ’2^{-2}) increase in surface irradiance with respect to the 2010-2019 mean due to a low median aerosol optical depth, and a 17.6 % (30.7 W māˆ’2^{-2}) increase due to several exceptionally dry days and a very low cloud fraction overall. Our analyses show that the reduced aerosols and contrails due to the COVID-19 measures are far less important in the irradiance record than the dry and particularly cloud-free weather.Comment: 21 pages, 12 figures, submitted to Communications Earth and Environmen

    The FOAM study : Is Hysterosalpingo foam sonography (HyFoSy) a cost-effective alternative for hysterosalpingography (HSG) in assessing tubal patency in subfertile women? Study protocol for a randomized controlled trial

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    This is an investigator initiated trial, VU medical center Amsterdam is the sponsor, contact information: prof. CJM de Groot, Department of Obstetrics and Gynaecology, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands, Tel: +ā€‰31-204444444. This study is funded by ZonMw, a Dutch organization for Health Research and Development, project number 837001504. ZonMW gives financial support for the whole project. IQ Medical Ventures provides the ExEm FOAMĀ® kits. The funding bodies have no role in the design of the study; collection, analysis, and interpretation of data; and in writing the manuscript.Peer reviewedPublisher PD

    Can hysterosalpingo-foam sonography replace hysterosalpingography as first-choice tubal patency test? A randomized non-inferiority trial

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    Funding Information: The FOAM study was an investigator-initiated study funded by ZonMw, The Netherlands organization for Health Research and Development (project number 837001504). ZonMw funded the whole project. IQ Medical Ventures provided the ExEm-foamVR kits free of charge. The funders had no role in study design, collection, analysis and interpretation of the data. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.Peer reviewedPublisher PD

    High resolution solar irradiance variability climatology dataset part 2: classifications, supplementary data, and statistics

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    Dataset description: High resolution surface solar irradiance series classification, cloud shadow and enhancement statistics, and satellite observations for studying intra-day surface solar irradiance variability. Part 2 of 2: This dataset is the derived from the 1 Hz observational record of direct, diffuse, and global horizontal irradiance measured by the Baseline Surface Radiation Network station at Cabauw, the Netherlands. More information about the observational site Cabauw can be found at the Ruisdael Observatory website. Methodology: An extensive dataset description is currently being written for Earth System Science Data. In the mean time, a more condensed description is available in preprint at Arxiv. Processing scripts are published at this Zenodo release. Dataset contents: This dataset contains daily time series with the following data, from 2011-02 until 2020-12-31: Cloud shadow and cloud enhancement time series classifications (see methodology) Overcast, clear-sky and variable time series classifications (see methodology) CAMS McClear for clear-sky global horizontal irradiance (version 3.5) CAMS McClear atmospheric composition input (aerosols, ozone, and total column water vapour) Solar elevation and azimuth angles (calculated using PySolar) Quality flags: non-official 1 Hz and official 1-minute (from BSRN at PANGAEA) Cabauw observatory tower wind speed and direction Additional satellite data time series from 2014-01 until 2016-12: MSGCPP satellite data for an area over central Netherlands (CLAAS2 source) Post processed timeseries of cloud types over Cabauw derived from this MSGCPP satellite data A nubiscope + satellite derived validation dataset for overcast and clear-sky classifications Statistics files: Cloud shadow and cloud enhancement event detection and event statistics based on the time series for 2011-2020 Daily radiation statistics for 2011-2020 And finally, for all days there are quicklooks available that visualize the irradiance time series, classification, and if available satellite data

    Data belonging to Record high solar irradiance in Western Europe during first COVID-19 lockdown largely due to unusual weather,

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    This data belongs to the paper Record high solar irradiance in Western Europe during first COVID-19 lockdown largely due to unusual weather, (soon to be) published in Communications Earth & Environment

    Reconciling Observations of Solar Irradiance Variability With Cloud Size Distributions

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    Clouds cast shadows on the surface and locally enhance solar irradiance by absorbing and scattering sunlight, resulting in fast and large solar irradiance fluctuations on the surface. Typical spatiotemporal scales and driving mechanisms of this intra-day irradiance variability are not well known, hence even 1 day ahead forecasts of variability are inaccurate. Here, we use long-term, high-frequency solar irradiance observations combined with satellite imagery, numerical simulations, and conceptual modeling to show how irradiance variability is linked to the cloud size distribution. Cloud shadow sizes are distributed according to a power law over multiple orders of magnitude, deviating only from the cloud size distribution due to cloud edge transparency at scales below ā‰ˆ750 m. Locally cloud-enhanced irradiance occurs as frequently as shadows, and is similarly driven mostly by boundary layer clouds, but distributed over a smaller range of scales. We reconcile studies of solar irradiance variability with those on clouds, which brings fundamental understanding to what drives irradiance variability. Our findings have implications not only for weather and climate modeling, but also for solar energy and photosynthesis by vegetation, where detailed knowledge of surface solar irradiance is essential

    Characterizing solar PV grid overvoltages by data blending advanced metering infrastructure with meteorology

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    If rooftop-installed solar energy systems generate more energy than locally consumed, the excess is fed into the electricity grid, increasing the voltage. Rising penetration levels of solar photovoltaic (PV) systems increase voltage levels, thereby threatening power quality. The extent to which solar PV cause grid issues in actual, nation-wide distribution grids, and how these issues correlate with cloud conditions and irradiance variability has yet to be quantified. This work provides a spatial and temporal characterization of overvoltage events linked to solar PV, using novel data sources. The analysis is based on over 200,000 events from advanced metering infrastructure (AMI) spanning 1/3rd of the Netherlands, combined with satellite observations and 1-minute irradiance measurements. As a result, we find that the typical duration of overvoltage events is in the order of 5 min, and frequently-reporting meters are geographically dispersed. While overvoltages are driven by high PV generation, we do not find evidence that local, short-term irradiance peaks result in additional events as compared to clear sky conditions. However, we do find that median overvoltage event occurrence on Sundays is more than 2.1 times that of weekdays, which can be related to low energy consumption. Our findings indicate PV hosting capacity to be reached throughout the service area simultaneously, and surprisingly show no reduction in event duration by inverter- or grid control. Notably, while a sharp increase in occurrence is observed, overvoltage events are still scarce in absolute terms, with only 0.1% of the AMI reporting more than 10 events in spring-summer 2020

    Outpatient treatment of worsening heart failure with intravenous and subcutaneous diuretics: a systematic review of the literature

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    Aims: In the coming decade, heart failure (HF) represents a major global healthcare challenge due to an ageing population and rising prevalence combined with scarcity of medical resources and increasing healthcare costs. A transitional care strategy within the period of clinical worsening of HF before hospitalization may offer a solution to prevent hospitalization. The outpatient treatment of worsening HF with intravenous or subcutaneous diuretics as an alternative strategy for hospitalization has been described in the literature. Methods and results: In this systematic review, the available evidence for the efficacy and safety of outpatient treatment with intravenous or subcutaneous diuretics of patients with worsening HF is analysed. A search was performed in the electronic databases MEDLINE and EMBASE. Of the 11 included studies 10 were single-centre, using non-randomized, observational registries of treatment with intravenous or subcutaneous diuretics for patients with worsening HF with highly variable selection criteria, baseline characteristics, and treatment design. One study was a randomized study comparing subcutaneous furosemide with intravenous furosemide. In a total of 984 unique individual patients treated in the reviewed studies, only a few adverse events were reported. Re-hospitalization rates for HF at 30 and 180 days were 28 and 46%, respectively. All-cause re-hospitalization rates at 30 and 60 days were 18ā€“37 and 22%, respectively. The highest HF re-hospitalization was 52% in 30 days in the subcutaneous diuretic group and 42% in 30 days in the intravenous diuretic group. Conclusions: The reviewed studies present practice-based results of treatment of patients with worsening HF with intravenous or subcutaneous diuretics in an outpatient HF care unit and report that it is effective by relieving symptoms with a low risk of adverse events. The studies do not provide satisfactory evidence for reduction in rates of re-hospitalization or improvement in mortality or quality of life. The conclusions drawn from these studies are limited by the quality of the individual studies. Prospective randomized studies are needed to determine the safety and effectiveness of outpatient intravenous or subcutaneous diuretic treatment for patient with worsening HF

    Effect of forced-air heaters on perfusion and temperature distribution during and after open-heart surgery

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    OBJECTIVES: After cardiopulmonary bypass, patients often show redistribution hypothermia, also called afterdrop. Forced-air blankets help to reduce afterdrop. This study explores the effect of forced-air blankets on temperature distribution and peripheral perfusion. The blood perfusion data is used to explain the observed temperature effects and the reduction of the afterdrop. METHODS: Fifteen patients were enrolled in a randomised study. In the test group (n=8), forced-air warmers were used. In the control group (n=7), only passive insulation was used. Core and skin temperatures and thigh temperatures at 0, 8, 18 and 38 mm depth were measured. Laser Doppler flowmetry (LDF) was used to record skin perfusion from the big toe. Blood flow through the femoral artery was determined with ultrasound. RESULTS: Afterdrop in the test group was smaller than in the control group (1.2+/-0.2 degrees C vs 1.8+/-0.7 degrees C: P=0.04) whilst no significant difference in mean tissue thigh temperature was found between the groups. Local skin temperature was 2.5-3.0 degrees C higher when using forced-air heaters. However, skin perfusion was unaffected. Ultrasound measurements revealed that leg blood flow during the first hours after surgery was reduced to approximately 70% of pre- and peri-operative values. CONCLUSIONS: Forced-air blankets reduce afterdrop. However, they do not lead to clinical relevant changes in deep thigh temperature. LDF measurements show that forced-air heating does not improve toe perfusion. The extra heat especially favours core temperature. This is underlined by the decrease in postoperative leg blood flow, suggesting that the majority of the warmed blood leaving the heart flows to core organs and not to the peripher
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