Rebutting existing misconceptions about multiple imputation as a method for handling missing data

Missing data is a problem that occurs frequently in many scientific areas. The most sophisticatedmethod for dealing with this problem is multiple imputation. Contrary to other methods, like listwise deletion, this method does not throw away information, and partly repairs the problem ofsystematic dropout. Although from a theoretical point of view multiple imputation is consideredto be the optimal method, many applied researchers are reluctant to use it because of persistentmisconceptions about this method. Instead of providing an(other) overview of missing data methods, or extensively explaining how multiple imputation works, this article aims specifically atrebutting these misconceptions, and provides applied researchers with practical arguments supporting them in the use of multiple imputation.Multivariate analysis of psychological dat

Advanced practice providers versus medical residents as leaders of rapid response teams:A 12-month retrospective analysis

Purpose In a time of worldwide physician shortages, the advanced practice providers (APPs) might be a good alternative for physicians as the leaders of a rapid response team. This retrospective analysis aimed to establish whether the performance of APP-led rapid response teams is comparable to the performance of rapid response teams led by a medical resident of the ICU. Material and methods In a retrospective single-center cohort study, the electronic medical record of a tertiary hospital was queried during a 12-months period to identify patients who had been visited by our rapid response team. Patient- and process-related outcomes of interventions of rapid response teams led by an APP were compared with those of teams led by a medical resident using various parameters, including the MAELOR tool, which measures the performance of a rapid response team. Results In total, 179 responses of the APP-led teams were analyzed, versus 275 responses of the teams led by a resident. Per APP, twice as many calls were handled than per resident. Interventions of teams led by APPs, and residents did not differ in number of admissions (p = 0.87), mortality (p = 0.8), early warning scores (p = 0.2) or MAELOR tool triggering (p = 0.19). Both groups scored equally on time to admission (p = 0.67) or time until any performed intervention. Conclusion This retrospective analysis showed that the quality of APP-led rapid response teams was similar to the quality of teams led by a resident. These findings need to be confirmed by prospective studies with balanced outcome parameters

Off-limb (spicule) DEM distribution from SoHO/SUMER observations

In the present work we derive a Differential Emission Measure (DEM) dis- tribution from a region dominated by spicules. We use spectral data from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on-board the Solar Heliospheric Observatory (SoHO) covering the entire SUMER wavelength range taken off-limb in the Northern polar coronal hole to construct this DEM distribution using the CHIANTI atomic database. This distribution is then used to study the thermal properties of the emission contributing to the 171 {\AA} channel in the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO). From our off-limb DEM we found that the radiance in the AIA 171 {\AA} channel is dominated by emission from the Fe ix 171.07 {\AA} line and has sparingly little contribution from other lines. The product of the Fe ix 171.07 {\AA} line contribution function with the off-limb DEM was found to have a maximum at logTmax (K) = 5.8 indicating that during spicule observations the emission in this line comes from plasma at transition region temperatures rather than coronal. For comparison, the same product with a quiet Sun and prominence DEM were found to have a maximum at logT max (K) = 5.9 and logTmax (K) = 5.7, respectively. We point out that the interpretation of data obtained from the AIA 171 {\AA} filter should be done with foreknowledge of the thermal nature of the observed phenomenon. For example, with an off-limb DEM we find that only 3.6% of the plasma is above a million degrees, whereas using a quiet Sun DEM, this contribution rises to 15%.Comment: 12 pages, 6 figures accepted by Solar Physic

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

The influence of media violence on youth

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83429/1/2003.Anderson_etal.InfluenceofMediaViolenceonYouth.PsychologicalScienceinthePublicInterest.pd

Zon op dijken : monitoring grasvegetatie onder zonnepanelen op dijken

Het plaatsen van zonnepanelen op dijken lijkt een goede optie om een bijdrage te leveren aan de productie van duurzame energie. Er zijn veel verschillende PV-systemen, die onderling verschillen in o.a. fundering en type panelen, met voor elk systeem een specifiek effect op de dijk. Aanleg, effect op de vegetatie, beheer en onderhoud zijn aspecten om in ogenschouw te nemen om PV-systemen te beoordelen op geschiktheid voor plaatsing op dijken.In 2020 is een project gestart in Ritthem (spuikom) en op de Knardijk bij Zeewolde om de mogelijkheden en effecten van een aantal opstellingen met zonnepanelen op dijken in kaart te brengen. De aanleg van PV-systemen en bekabeling is een specifiek onderdeel met mogelijke schade aan het talud en de grasmat. Binnen een paar maanden na plaatsing van de zonnepanelen in Ritthem (standaardopstellingen met tafels zoals ook gebruikt op land) was al duidelijk dat de grasmat onder de panelen grote schade opliep. Ook onder de glas/glas-panelen kwam veel te weinig licht om de grasmat op een voldoende kwaliteitsniveau te houden. De combinatie van met name minder zonlicht (reductie tot 90%), een nat najaar en beweiding met schapen zorgde voor een erg open zode met gedeelten van slechts 10% grondbedekking. In het volgende voorjaren en zomers trad geen herstel van de grasmat op. Door de lage opstelling was het onderhoud (maaien) onder de panelen erg lastig. Aanpassing van een aantal opstellingen (lichtreductie maximaal 50%) met minder zonnepanelen in Ritthem zorgde voor een duidelijk herstel van de grasmat. De grondbedekking was met 75 tot 85% nog wel lager dan de gedeelten zonder schaduwwerking van zonnepanelen (grondbedekking van meer dan 90%) en daarmee aan de ondergrens van wat wenselijk is op een dijk. Tevens is waargenomen dat de beworteling als gevolg van de minder licht omstandigheden bij een reductie van 50% licht slechter was in diepte en intensiteit ten opzicht van geen lichtreductie. De opstelling op de Knardijk met betonblokken boven en onderaan de dijk en daartussen hangende panelen aan kabels beïnvloedde de grasmat niet negatief in de beoordelingsperiode van 1 jaar, ondanks de lichtreductie tot 30% op een aantal gedeelten onder de traveeën van hangende panelen. Het maaien van dit dijkgedeelte was wel erg lastig vanwege de kabels en de panelen. Beheerders zijn ook terughoudend, omdat ze geen schade willen aanbrengen aan de opstellingen