41 research outputs found
Fluid inclusion study of the Horní Luby cinnabar deposit, Saxothuringian Zone, Bohemian Massif: clues for the metamorphic remobilization of mercury
Tetrahedrite-(Hg), a new 'old' member of the tetrahedrite group
Tetrahedrite-(Hg), Cu6(Cu4Hg2)Sb4S13, has been approved as a new mineral species using samples from Buca della Vena mine (hereafter BdV), Italy, Jedová hora (Jh), Czech Republic and RoŽÅ 1/2ava (R), Slovakia. It occurs as anhedral grains or as tetrahedral crystals, black in colour, with metallic lustre. At BdV it is associated with cinnabar and chalcostibite in dolomite veins. At Jh, tetrahedrite-(Hg) is associated with baryte and chalcopyrite in quartz-siderite-dolomite veins; at R it is associated with quartz in siderite-quartz veins. Tetrahedrite-(Hg) is isotropic, greyish-white in colour, with creamy tints. Minimum and maximum reflectance data for Commission on Ore Mineralogy wavelengths in air (BdV sample), R in %) are 32.5 at 420 nm; 32.9 at 546 nm; 33.2 at 589 nm; and 30.9 at 650 nm. Chemical formulae of the samples studied, recalculated on the basis of 4 (As + Sb + Bi) atoms per formula unit, are: (Cu9.44Ag0.07)Σ9.51(Hg1.64Zn0.36Fe0.06)Σ2.06Sb4(S12.69Se0.01)Σ12.70 (BdV), Cu9.69(Hg1.75Fe0.25Zn0.06)Σ2.06(Sb3.94As0.06)S12.87 (Jh) and (Cu9.76Ag0.04) Σ9.80(Hg1.83Fe0.15Zn0.10)Σ2.08(Sb3.17As0.58Bi0.25)S13.01 (R). Tetrahedrite-(Hg) is cubic, I3m, with a = 10.5057(8) Å, V = 1159.5(3) Å3 and Z = 2 (BdV). Unit-cell parameters for the other two samples are a = 10.4939(1) Å and V = 1155.61(5) Å3 (Jh) and a = 10.4725(1) Å and V = 1148.55(6) Å3 (R). The crystal structure of tetrahedrite-(Hg) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.019 on the basis of 335 reflections with Fo > 4σ(Fo) and 20 refined parameters. Tetrahedrite-(Hg) is isotypic with other members of the tetrahedrite group. Mercury is hosted at the tetrahedrally coordinated M(1) site, along with minor Zn and Fe. The occurrence of Hg at this position agrees both with the relatively large M(1)-S(1) bond distance (2.393 Å) and the refined site scattering. Previous occurrences of Hg-rich tetrahedrite and tetrahedrite-(Hg) are reviewed, and its relations with other Hg sulfosalts are discussed
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Variations in Multiple Birth Rates and Impact on Perinatal Outcomes in Europe
Objective
Infants from multiple pregnancies have higher rates of preterm birth, stillbirth and neonatal death and differences in multiple birth rates (MBR) exist between countries. We aimed to describe differences in MBR in Europe and to investigate the impact of these differences on adverse perinatal outcomes at a population level.
Methods
We used national aggregate birth data on multiple pregnancies, maternal age, gestational age (GA), stillbirth and neonatal death collected in the Euro-Peristat project (29 countries in 2010, N = 5 074 643 births). We also used European Society of Human Reproduction and Embryology (ESHRE) data on assisted conception and single embryo transfer (SET). The impact of MBR on outcomes was studied using meta-analysis techniques with random-effects models to derive pooled risk ratios (pRR) overall and for four groups of country defined by their MBR. We computed population attributable risks (PAR) for these groups.
Results
In 2010, the average MBR was 16.8 per 1000 women giving birth, ranging from 9.1 (Romania) to 26.5 (Cyprus). Compared to singletons, multiples had a nine-fold increased risk (pRR 9.4, 95% Cl 9.1–9.8) of preterm birth (<37 weeks GA), an almost 12-fold increased risk (pRR 11.7, 95% CI 11.0–12.4) of very preterm birth (<32 weeks GA). Pooled RR were 2.4 (95% Cl 1.5–3.6) for fetal mortality at or after 28 weeks GA and 7.0 (95% Cl 6.1–8.0) for neonatal mortality. PAR of neonatal death and very preterm birth were higher in countries with high MBR compared to low MBR (17.1% (95% CI 13.8–20.2) versus 9.8% (95% Cl 9.6–11.0) for neonatal death and 29.6% (96% CI 28.5–30.6) versus 17.5% (95% CI 15.7–18.3) for very preterm births, respectively).
Conclusions
Wide variations in MBR and their impact on population outcomes imply that efforts by countries to reduce MBR could improve perinatal outcomes, enabling better long-term child health
Clarity and consistency in stillbirth reporting in Europe: why is it so hard to get this right?
Background
Stillbirth is a major public health problem, but measurement remains a challenge even in high-income countries. We compared routine stillbirth statistics in Europe reported by Eurostat with data from the Euro-Peristat research network.
Methods
We used data on stillbirths in 2015 from both sources for 31 European countries. Stillbirth rates per 1000 total births were analyzed by gestational age (GA) and birthweight groups. Information on termination of pregnancy at ≥22 weeks’ GA was analyzed separately.
Results
Routinely collected stillbirth rates were higher than those reported by the research network. For stillbirths with a birthweight ≥500 g, the difference between the mean rates of the countries for Eurostat and Euro-Peristat data was 22% [4.4/1000, versus 3.5/1000, mean difference 0.9 with 95% confidence interval (CI) 0.8–1.0]. When using a birthweight threshold of 1000 g, this difference was smaller, 12% (2.9/1000, versus 2.5/1000, mean difference 0.4 with 95% CI 0.3–0.5), but substantial differences remained for individual countries. In Euro-Peristat, missing data on birthweight ranged from 0% to 29% (average 5.0%) and were higher than missing data for GA (0–23%, average 1.8%).
Conclusions
Routine stillbirth data for European countries in international databases are not comparable and should not be used for benchmarking or surveillance without careful verification with other sources. Recommendations for improvement include using a cut-off based on GA, excluding late terminations of pregnancy and linking multiple sources to improve the quality of national databases.publishedVersio
Perinatal health monitoring through a European lens: eight lessons from the Euro-Peristat report on 2015 births
International audienceNo abstract availabl
Vulnerable newborn types: Analysis of population-based registries for 165 million births in 23 countries, 2000-2021.
OBJECTIVE: To examine the prevalence of novel newborn types among 165 million live births in 23 countries from 2000 to 2021. DESIGN: Population-based, multi-country analysis. SETTING: National data systems in 23 middle- and high-income countries. POPULATION: Liveborn infants. METHODS: Country teams with high-quality data were invited to be part of the Vulnerable Newborn Measurement Collaboration. We classified live births by six newborn types based on gestational age information (preterm 90th centile) for gestational age, according to INTERGROWTH-21st standards. We considered small newborn types of any combination of preterm or SGA, and term + LGA was considered large. Time trends were analysed using 3-year moving averages for small and large types. MAIN OUTCOME MEASURES: Prevalence of six newborn types. RESULTS: We analysed 165 017 419 live births and the median prevalence of small types was 11.7% - highest in Malaysia (26%) and Qatar (15.7%). Overall, 18.1% of newborns were large (term + LGA) and was highest in Estonia 28.8% and Denmark 25.9%. Time trends of small and large infants were relatively stable in most countries. CONCLUSIONS: The distribution of newborn types varies across the 23 middle- and high-income countries. Small newborn types were highest in west Asian countries and large types were highest in Europe. To better understand the global patterns of these novel newborn types, more information is needed, especially from low- and middle-income countries
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Neonatal Mortality Disparities by Gestational Age in European Countries
Importance
There are wide disparities in neonatal mortality rates (NMRs, deaths &amp;lt;28 days of life after live birth per 1000 live births) between countries in Europe, indicating potential for improvement. Comparing country-specific patterns of births and deaths with countries with low mortality rates can facilitate the development of effective intervention strategies.
Objective
To investigate how these disparities are associated with the distribution of gestational age (GA) and GA-specific mortality rates.
Design, Setting, and Participants
This was a cross-sectional study of all live births in 14 participating European countries using routine data compiled by the Euro-Peristat Network. Live births with a GA of 22 weeks or higher from 2015 to 2020 were included. Data were analyzed from May to October 2023.
Exposures
GA at birth.
Main Outcomes and Measures
The study investigated excess neonatal mortality, defined as a rate difference relative to the pooled rate in the 3 countries with the lowest NMRs (Norway, Sweden, and Finland; hereafter termed the top 3). The Kitagawa method was used to divide this excess into the proportion explained by the GA distribution of births and by GA-specific mortality rates. A sensitivity analysis was conducted among births 24 weeks’ GA or greater.
Results
There were 35 094 neonatal deaths among 15 123 428 live births for an overall NMR of 2.32 per 1000. The pooled NMR in the top 3 was 1.44 per 1000 (1937 of 1 342 528). Excess neonatal mortality compared with the top 3 ranged from 0.17 per 1000 in the Czech Republic to 1.82 per 1000 in Romania. Excess deaths were predominantly concentrated among births less than 28 weeks’ GA (57.6% overall). Full-term births represented 22.7% of the excess deaths in Belgium, 17.8% in France, 40.6% in Romania and 17.3% in the United Kingdom. Heterogeneous patterns were observed when partitioning excess mortality into the proportion associated with the GA distribution vs GA-specific mortality. For example, these proportions were 9.2% and 90.8% in France, 58.4% and 41.6% in the United Kingdom, and 92.9% and 7.1% in Austria, respectively. These associations remained stable after removing births under 24 weeks’ GA in most, but not all, countries.
Conclusions and Relevance
This cohort study of 14 European countries found wide NMR disparities with varying patterns by GA. This knowledge is important for developing effective strategies to reduce neonatal mortality
