Begravede dale i Jylland og på Fyn - nu på internettet!

De jysk-fynske amters Grundvandssamarbejde har igennem de seneste 6 år udført en kortlægning af begravede dale i Jylland og på Fyn. Grundvandssamarbejdet giver mulighed for at få gennemført mere regionalt dækkende projekter på tværs af amtsgrænserne, og de begravede dalsystemer respekterer jo netop ikke amtsgrænser

A 3D GEOLOGICAL MODEL OF THE NASIA SUB-BASIN, NORTHERN GHANA-INTERPRETATIONS FROM THE INVERSION RESULTS OF REPROCESSED GEOTEM DATA

Inversion of regional-scale airborne electromagnetic (AEM) data was used in building a 3D geologic model of the Nasia Sub-Basin, Northern Ghana. Geological interpretation of the AEM data was guided by a priori knowledge obtained from previous research in the area, geological maps and reports. A key requirement of the modelling process was to define the subsurface stratigraphy of the area, chiefly to provide 1) a detailed stratigraphical context for hydrogeologic use, 2) a repository of comprehensive stratigraphic knowledge of the study area which will be easily accessible. The AEM measurements, consisting of GEOTEM data, was originally collected for mineral exploration purposes. The B-field data have been (re)processed to enhance the resolution and inverted by using spatial constraints to preserve the lateral and vertical coherence. During the processing and inversion phases, the regularization strategies and associated parameters have been tuned by following an iterative approach characterized by a tight collaboration between geologists and geophysicists to retrieve the geophysical model that is in the best agreement, not only with the geophysical data, but also with the geological expectations. The new (pseudo-)3D inversion showed very different features with respect to the previous Conductivity-Depth Images (CDI). The new geophysical model led to new interpretations of the geological settings and to the construction of a comprehensive 3D geomodel of the basin based on the integration of AEM and borehole information. Nevertheless, in order to have a model, suitable for hydrogeological characterization, it will be necessary to include more details regarding the upper, weathered zone as the AEM survey was optimized to have a very deep penetration and not an extremely high shallow resolution. These aspects will be remedied by the inclusion, for example, of the interpretations from Electrical Resistivity Tomography (ERT) data, which will provide the necessary resolution in the upper sections

Serum Concentrations of Antibodies Against Vaccine Toxoids in Children Exposed Perinatally to Immunotoxicants

Background: Polychlorinated biphenyls (PCBs) may cause immunotoxic effects, but the detailed dose–response relationship and possible vulnerable time windows of exposure are uncertain. In this study we applied serum concentrations of specific antibodies against childhood vaccines as sentinels of immunotoxicity. Objectives: The main objective was to assess the possible dependence of antibody concentrations against diphtheria and tetanus toxoids in children with regard to prenatal and postnatal PCB exposures. Methods: From a cohort of 656 singleton births formed in the Faroe Islands during 1999–2001, children were invited for examination with assessment of serum antibody concentrations at 5 years (before and after a booster vaccination) and at 7 years of age. Total PCB concentrations were determined in serum from ages 5 and 7 years, and data were also available on PCB concentrations in maternal pregnancy serum, maternal milk, and, for a subgroup, the child’s serum at 18 months of age. Results: A total of 587 children participated in the examinations at ages 5 and/or 7 years. At age 5 years, before the booster vaccination, the antidiphtheria antibody concentration was inversely associated with PCB concentrations in milk and 18-month serum. Results obtained 2 years later showed an inverse association of concentrations of antibodies against both toxoids with PCB concentrations at 18 months of age. The strongest associations suggested a decrease in the antibody concentration by about 20% for each doubling in PCB exposure. At age 5 years, the odds of an antidiphtheria antibody concentration below a clinically protective level of 0.1 IU/L increased by about 30% for a doubling in PCB in milk and 18-month serum. Conclusions: Developmental PCB exposure is associated with immunotoxic effects on serum concentrations of specific antibodies against diphtheria and tetanus vaccinations. The immune system development during the first years of life appears to be particularly vulnerable to this exposure

Neurobehavioral deficits at age 7 years associated with prenatal exposure to toxicants from maternal seafood diet

To determine the possible neurotoxic impact of prenatal exposure to polychlorinated biphenyls (PCBs), we analyzed banked cord blood from a Faroese birth cohort for PCBs. The subjects were born in 1986–1987, and 917 cohort members had completed a series of neuropsychological tests at age 7 years. Major PCB congeners (118, 138, 153, and 180), the calculated total PCB concentration, and the PCB exposure estimated in a structural equation model showed weak associations with test deficits, with statistically significant negative associations only with the Boston Naming test. Likewise, neither hexachlorobenzene nor p,p'-dichlorodiphenyldichloroethylene showed clear links to neurobehavioral deficits. Thus, these associations were much weaker than those associated with the cord-blood mercury concentration, and adjustment for mercury substantially attenuated the regression coefficients for PCB exposure. When the outcomes were joined into motor and verbally mediated functions in a structural equation model, the PCB effects remained weak and virtually disappeared after adjustment for methylmercury exposure, while mercury remained statistically significant. Thus, in the presence of elevated methylmercury exposure, PCB neurotoxicity may be difficult to detect, and PCB exposure does not explain the methylmercury neurotoxicity previously reported in this cohort

ræsonnementer i folkeskolens matematikundervisning – karakterisering, initiering, identificering og vurdering af ræsonnementskompetencen

Med introduktionen af kompetencetænkning i Fælles Mål 2009 fik folkeskolens matematiklærereen ny udfordring i forhold til planlægning, gennemførelse og evaluering af undervisning. Påbaggrund af et udviklingsarbejde beskrives det hvordan udformningen af elevaktiviteter, herunderisær oplægget, har betydning for initiering og udvikling af ræsonnementskompetence og lærerensmulighed for at kunne evaluere kompetencens udvikling. (a) I oplægget skal det tydeliggøres at måleter at gennemføre eksplicitte ræsonnementer, (b) aktiviteten skal være udfordrende i den forstand atden yder faglig modstand, og (c) der kan eventuelt aftales “spilleregler” der forpligter eleverne på atargumentere. Artiklen rummer endvidere en almen diskussion af kompetencebegrebet samt overvejelserom evaluering heraf