Crowded-field photometry from HST-imaging

We present a thorough investigation of stellar photometry based on HST imaging of crowded fields at 85 and 10 arcsec from the centre of the high-surface brightness elliptical M32. The Principal Investigators of the present archive data have elsewhere presented an impressive colour-magnitude diagram of the field at 85 arcsec. Based on the same data we enlarge on their photometric analysis and supplement with error estimators that more clearly show the implications of severe image crowding on the stellar photometry. We show that the faintest stars (I>25.0, V>26.0) are found too bright by several tens of a magnitude. For the field at 10 arcsec we conclude that it is not possible to obtain reliable stellar photometry, standard deviations being larger than 0.4 mag. Artificial-star experiments show that only very few of the brightest stars of the luminosity function can be expected to represent single objects, the majority being either spurious or not as bright as measured.Comment: 7 pages, to be published in Astronomy and Astrophysic

Using Decision Tree Analysis and GIS in Modelling (semi)VOC Emissions at the European Scale

Risk assessment of semi Volatile Organic Compounds (semi-VOCs) is a fundamental part in the regulation of production and use in industries and households. Emission inventories are a natural starting point in risk assessments and, given the complex use and emission patterns of the many thousands VOCs, emission estimates are often one of the most uncertain and problematic parts in risk assessments. Some critical issues are quantifying production and use amounts of chemicals and chemical containing products, assigning amounts to industrial activities and household products, identifying use and emission patterns, identifying receiving environmental compartment and quantifying the emission to these, which depend on production volumes, chemical properties, and their mode of use, in a non-trivial way. To ensure reliable risk assessments, emission estimates are sought which need to be realistic and, at the same time, do not require excessive effort in the modeling of emission inventories. The report proposes a method to capitalize on the information in the European Chemicals Bureau risk assessment reports (RARs), available for a limited number of chemicals, to train decision trees that allow estimating emissions of chemicals to different environmental compartments. The report also illustrates how these estimates can be used in conjunction with geographic information system (GIS) processing of spatial data to map emissions. Examples are drawn with reference to the case of the European Union. It is shown how quick, spatially distributed estimates of emissions to specific environmental compartments can be obtained to be used in screening level assessment. The method outlined in the report allows a quick and reliable estimation of the fraction of total chemical production that results in emission to a specific environmental medium, using data mining techniques and GIS. This can result helpful within the new procedures for risk assessments guided by REACH, as a way to exploit data from existing risk assessments for predicting and mapping emissions of chemicals that have not yet been assessed.JRC.H.5-Rural, water and ecosystem resource

Matematikhistoriske originalkilder, ræsonnementskompetence og GeoGebra på mellemtrinnet

Ph.d.-afhandlingen præsenterer forskellige didaktiske principper, der kan understøtte, at elever får mulighed for at udvikle deres ræsonnementskompetence, når de arbejder med samspillet mellem originalkilder og GeoGebra. Ph.d.-afhandlingen tager afsæt i Design Based Research og placerer sig mellem tre forskningsområder: 1) Matematikkens historie, herunder brug af originalkilder, 2) Digitale teknologier i matematikundervisningen og 3) Matematiske ræsonnementer. Den består af tre delundersøgelser: 1) Et review, 2) en analyse af udvalgte kapitler fra et lærebogssystem og 3) planlægning og analyse af tre afprøvninger. Det teoretiske omdrejningspunkt er distinktionerne mellem den undersøgende og produktive side af ræsonnementskompetencen (Niss & Jensen, 2002), epistemisk, pragmatisk og retfærdiggørende medieringer (fx Misfeldt og Jankvist, 2018), regel- og strukturopfattelse samt statisk og dynamisk læsning (Mellin-Olsen, 1984). Derudover inddrages Jensens (2011) beskrivelse af historisk bevidsthed

Hvordan kan hytteklimaet forbedres i sommervarmen?

Hvordan kan hytteklimaet forbedres i sommervarmen

Test og scoring af farehytter

Præsentation: Et forsøg der undersøger fordele og ulemper i de forskellige farehytte designs. Alle informationer er beskrevet i kataloget

Potentialer i forskellige hyttedesign

Gennemgang af; Farehyttens betydning for pattegrisenes overlevelse, Farehytter i Danmark, Hyttekatalog, Test af farehytter og Huske-seddel ved valg af farehytte

Influence of family size and birth order on risk of cancer: a population-based study

<p>Abstract</p> <p>Background</p> <p>Family size and birth order are known to influence the risk of some cancers. However, it is still unknown whether these effects change from early to later adulthood. We used the data of the Swedish Family-Cancer Database to further analyze these effects.</p> <p>Methods</p> <p>We selected over 5.7 million offspring with identified parents but no parental cancer. We estimated the effect of birth order and family size by Poisson regression adjusted for age, sex, period, region and socioeconomic status. We divided the age at diagnosis in two groups, below and over 50 years, to identify the effect of family size and birth order for different age periods.</p> <p>Results</p> <p>Negative associations for increasing birth order were found for endometrial, testicular, skin, thyroid and connective tissue cancers and melanoma. In contrast, we observed positive association between birth order and lung, male and female genital cancers. Family size was associated with decreasing risk for endometrial and testicular cancers, melanoma and squamous cell carcinoma; risk was increased for leukemia and nervous system cancer. The effect of birth order decreased for lung and endometrial cancer from age at diagnosis below to over 50 years. Combined effects for birth order and family size were marginally significant for thyroid gland tumors. Especially, the relative risk for follicular thyroid gland tumors was significantly decreased for increasing birth order.</p> <p>Conclusion</p> <p>Our findings suggest that the effect of birth order decreases from early to late adulthood for lung and endometrial cancer.</p