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Most pegmatites of southern Norway seem to be derived from anatectic melting of metamorphic rocks during the Sveconorwegian orogeny rather than to be highly evolved residual melts derived from granites. We test this hypothesis by providing new age data for thirteen pegmatites and one granite. Based on these new age data, we distinguish two age groups of Sveconorwegian pegmatites (>1,000 m3 in size); Group 1: 1100–1030 Ma and Group 2: 930–890 Ma. All pegmatites except those from the Østfold area crystallized significantly earlier or later than adjacent granites. The Tørdal granite, yielding an age of 946 ± 4 Ma, is about 40 Ma older than the adjacent pegmatites. Field evidence and the age difference between pegmatites and granites supports an anatectic origin for these pegmatites. Sources of these pegmatite melts are biotite- and biotite-amphibole gneisses and amphibolites. Group 1 pegmatites formed in transpressional regimes after peak metamorphism, whereas Group 2 pegmatites formed in an extensional regime and the required heat for partial melting was provided by mafic magma underplating. Differences in the rheological behavior of amphibolite and granitic gneiss during extensional tectonics are the major reason why Group 2 pegmatites occur preferentially in large amphibolite bodies. Under mid-crustal conditions, amphibolite reacts brittle to semi-brittle forming open structures in an extensional tectonic regime where partial melts drained into. Granitic gneisses react in a ductile manner and do not have the ability to drain partial melt. Pegmatite formation in the Grenville Province, i.e., the Laurentian part of the Grenville–Sveconorwegian orogenic belt, formed between ca. 1090 and 980 Ma peaking at 1010 to 980 Ma. Thus, the Grenville peak postdates the Sveconorwegian Group 1 peak by about 30 Ma. These pegmatites formed in similar orogenic settings, implying that similar tectono-metamorphic developments along the Grenville–Sveconorwegian orogenic belt were diachronous. We conclude that local anatexis is the major pegmatite-melt forming process in the Sveconorwegian as well as Grenville orogen. Local anatexis also may be important in other pegmatite provinces.

The primitive cells that emerged at the origin of life are commonly viewed as spherical biosurfactant shells, freely suspended in aqueous media1–3. This model explains initial, but not subsequent events in the development process towards structured protocells. Taking into consideration the involvement of naturally occurring surfaces, which were abundant on the early Earth4, we report feasible and productive pathways for the development of primitive cells. Surfaces intrinsically possess energy, easily utilized by the interfacing amphiphiles, such as lipids, to attain self-organization and spontaneous transformations5–7. We show that the physical interaction of phospholipid pools with 20 Hadean Earth analogue materials as well as a Martian meteorite composed of fused regolith representing the ancient crust of Mars, consistently lead to the shape transformation and autonomous formation of surfactant compartment assemblies. Dense, colony-like protocell populations grow from these lipid deposits, predominantly at the grain boundaries or cleavages of the investigated natural surfaces, and remain there for several days. The model protocells in our study are able to autonomously develop, transform and pseudo-divide, and encapsulate RNA as well as DNA. We also demonstrate that they can accommodate non-enzymatic, DNA strand displacement reactions. Our findings suggest a feasible route towards the transformation from nonliving to living entities, and provide fresh support for the ‘Lipid World’ hypothesis8.

The boron isotopic composition of tourmaline and hambergite (Be2BO3[OH,F]) from peraluminous (n = 12), peralkaline (n = 1), and peralkaline nepheline syenite (n = 16) pegmatites has been measured by secondary ion mass spectrometry, for which a new hambergite reference material was developed. The focus of this study is on nepheline syenite pegmatites from the Larvik Plutonic Complex (Norway) and one peralkaline pegmatite related to the nearby Eikeren-Skrim Complex (Norway), where we investigate the source of boron as being from magmatic vs. external fluids. Tourmaline-hambergite mineral pairs were also analysed from peraluminous pegmatite localities (Russia, Tajikistan, and Pakistan) to test for systematic B-isotope fractionation between these two minerals. Tourmaline and hambergite from peraluminous granitic pegmatites have light boron ratios (δ11B = −12.9to −1.0‰) associated with S-type granites, whereas peralkaline granitic and nepheline syenite pegmatites have boron ratios (δ11B = −1.7 to 11.8‰), which we interpret is a result of heavy‑boron enrichment from external fluids. Our data show that hambergite tracks isotope variations of its geochemical setting and could therefore be used as a proxy mineral in place of tourmaline when geochemical stability favours hambergite. The results suggest a slight but consistent partitioning of B-isotopes between tourmaline and hambergite, with Δ11B = δ11Btourmaline−δ11Bhambergite in the range of approximately −3‰ to −5‰. Boron is in trigonal coordination with oxygen in both of these mineral phases as verified by NMR. Single crystal XRD analyses of tourmaline and hambergite reveal consistent longer distances of tourmaline relative to hambergite. We attribute the boron isotopic fractionation to the longer bond-lengths in tourmaline compared with hambergite.

To identify predictors and define reference values for T lymphocyte subsets in HIV negative pregnant black women.Cross sectional study.Edith Opperman Martenity Hospital, Harare, Zimbabwe.1113 HIV negative women 22 to 35 weeks pregnant registering for routine antenatal care.A questionnaire was used to collect demographic and obstetric data. CD4 and CD8 T lymphocyte counts were determined by manual immunocytochemistry. Concentrations in serum, of retinol, beta-carotene, ferritin, folate and 1-antichymotrypsin were also measured. Multiple linear regression analysis was employed to identify and estimate effects of potential predictors.CD4 and CD8 T lymphocyte levels, demographic, obstetric data and micronutrient status.Predictors of CD4 counts were gestational age, serum retinol and season. CD4 counts declined by 25 (95% confidence interval [CI]; 11 to 40; p = 0.001) cells/L for each week's increase in gestation among women with low serum retinol, while low serum retinol was independently associated with lower CD4 counts (-127; 95% CI, -233 to 20 cells/L; p = 0.02) at 35 weeks gestation. The late rainy season was associated with higher CD4 counts (137; 95% CI, 67 to 207 cells/L; p0.001). CD8 counts were higher in women with low serum folate (87; 95% CI, 6 to 166 cells/L; p = 0.036) and were slightly higher in gravida 4+ compared to gravida one to three. Reference values of CD4 but not CD8 count and percentage markedly differed from flow cytometry values of pregnant and non-pregnant women in developed and developing countries reported in the literature, even after controlling for the differences in methods of T lymphocyte subset immunophenotyping.Gestational age, gravidity, micronutrient status and season influence T lymphocyte subset levels and need to be considered when designing clinical management and intervention strategies for pregnant women. The data underscores the need for local reference values.

Erythromycin resistance was analyzed in 280,415 Danish Staphylococcus aureus strains isolated from hospitalized patients and phage-typed in the period 1967 to 1987. Multiresistant, erythromycin-resistant strains decreased during the whole period, while strains resistant only to penicillin and erythromycin increased after 1972. This increase coincided with an increase in erythromycin consumption in Denmark from 0.4 DDD/1000 persons/day in 1978 to 1.9, in 1987. Erythromycin consumption in nine large Danish hospitals was significantly associated with the level of erythromycin-resistant S. aureus at the hospitals.

The worldwide use of antibiotics is increasing with increasing costs and resistant bacteria as a consequence. The Danish use of antibiotics is one of the lowest in DDD/1,000 inhabitants/year; however, the use of ampicillin and co-trimoxazole has been found to be too high. An information campaign in the beginning of 1987, using written material, stressed the importance of reducing the ampicillin and co-trimoxazole and increasing the penicillin usage in Denmark. This campaign was followed up by 10 lectures given by the same person in two (I and II) of the five counties of Zealand, Denmark. In county I, the lectures were given in meetings arranged by the local department of clinical microbiology. In county II, the lectures were given at meetings sponsored by a pharmaceutical company. The prescribing habits were generally changed significantly. In county I, the changes were significantly higher compared with counties only receiving written material. In county II, the prescribing habits did not change further compared with the counties only receiving written material. It is concluded that face-to-face information can improve the efficacy of written information, but sponsorship by pharmaceutical companies may weaken this efficacy.

High-risk human papillomavirus (HPV) is responsible for cervical cancer and genital Schistosoma haematobium infection has been hypothesized to be an additional co-factor or even an independent risk factor for cervical neoplasia. The present study aimed to investigate the impact of schistosomiasis on HPV persistence and development of cell atypia in a group of rural Zimbabwean women with confirmed high-risk HPV.A five-year follow-up was done among women previously included in a study on genital schistosomiasis. Women who had high-risk HPV at baseline were invited after 5 years for examination of cell atypia, genital schistosomiasis, and high-risk HPV. Both vaginal lavage samples (low-cost) and cervix brush samples (high-cost) were obtained for further analysis.Thirty-seven women were re-examined. Genital Schistosoma haematobium of a minimum of five years' duration was associated with the development high-grade squamous intraepithelial neoplasia, but not with persistent high-risk HPV. There was a high concordance between the brush and vaginal lavage (96.3% agreement, kappa 0.93); however, the number of beta-globin negative vaginal lavage samples was unacceptably high.Findings warrant an exploration in a larger longitudinal study where a vaginal swab should be explored.

A number of trials on maternal multi-micronutrient supplementation (MMS) have found a benefical effect on birth weight, but few have demonstrated a beneficial effect on infant survival. We examined the effect of two different preparations of antenatal MMS on fetal loss and under-2-years child mortality, as compared with iron-folic acid supplementation among 2,100 pregnant women in Guinea-Bissau. Women receiving a 1xRDA MMS preparation (consisting of 14 vitamins and minerals) had a marginally reduced risk of fetal loss (Relative risk (RR) 0.65, 95% CI 0.40; 1.05), and women receiving a 2xRDA MMS preparation had a similar effect (RR 0.67, 95% CI 0.42; 1.08), the pooled effect being 0.66 (95% CI 0.44; 0.99). None of the supplements reduced under-2-years mortality or the combination of fetal loss and under-2-years mortality. There was a marginally negative effect of both the 1xRDA (RR 2.10, 95% CI 0.99; 4.46) and the 2xRDA (RR 2.02, 95% CI 0.95; 4.32) MMS preparation on mortality specifically between 92]365 days of age. (Afr. J. Reprod. Health 2010; 14[2]:17-26).

Udgivelsesdato: 2009