Widespread CO2-rich cordierite in the UHT Bakhuis granulite belt, Surinam

The Bakhuis Granulite Belt, approx. 30 x 100 km, transects the large Paleoproterozoic greenstone belt along the north-eastern coast of South America. Part of the Granulite belt witnessed typical Ultrahigh-Temperature Metamorphism (UHTM). A metapelite area in the NE of the belt shows assemblages characteristic of UHTM: aluminous (up to 10 wt.%) orthopyroxene + sillimanite +/- sapphirine. Leucosomes commonly show mesoperthite or K-rich antiperthite. Ternary feldspar thermometry indicates a peak temperature of 1000-1050°C and pressure is estimated to have been around 9 kbar. Metapelites elsewhere in the belt lack mineral assemblages characteristic of UHTM. However, feldspar thermometry for these metapelites as well as for mesoperthite granulites indicates that peak temperatures were 900°C or higher throughout the belt and locally reached 1000-1050°C. It is, therefore, concluded that the other parts of the belt also witnessed UHTM, despite their lack of typical UHTM assemblages. Study of peak assemblages in metapelites in these parts is hampered by varying, but usually considerable retrograde metamorphism. The main mafic mineral in metapelites is coarse Mg-rich cordierite, accompanied by coarse sillimanite. Widespread occurrence of cordierite + sillimanite in metapelites is unusual for UHTM, the more so as UHTM assemblages are commonly formed at the expense of cordierite-bearing assemblages. In a small part of the metapelites cordierite is accompanied by coarse aluminous (up to 9 wt.%) orthopyroxene. Associated cordierite and orthopyroxene appear to have formed in equilibrium with each other. Only the presence of aluminous orthopyroxene (as well as the presence of mesoperthite) is typical for UHTM, but is limited to a small part of the metapelites. Peak P-T conditions for the cordierite-bearing part of the belt are estimated to have been similar to those in the NE area with its characteristic UHTM assemblages. Primary and secondary fluid inclusions in UHT quartz blebs in orthopyroxene consist of pure CO2 and have a high density. Raman spectroscopy indicated a considerable CO2 content in cordierite. Estimated from their birefringence, the CO2 content of most cordierites is in the range of 1-2 wt.% CO2. This corresponds to a substantial filling of the cordierite channels with CO2 and for the higher levels possibly near-saturation with CO2 according to the model of Harley and Thompson for the maximum level of CO2 in cordierite. Thermodynamic data for CO2-rich cordierite are poorly known. However, a high level of CO2 in cordierite has been considered to lead to a substantial expansion of its stability field, also into the field of UHTM, at T > 900°C. This is, therefore, assumed to be the explanation for the unusual, widespread occurrence of cordierite in the UHTM belt. A small part of the metapelite samples shows cordierite of a high birefringence, twice that of quartz. SIMS analysis of such cordierite showed 3.0 wt.% CO2, the highest level known from nature. The level is far too high to have formed at UHTM conditions according to the model of Harley and Thompson and would be possible only at conditions such as 700°C and 10 kbar. It is assumed that locally the CO2 level of cordierite changed after UHTM, by taking up additional CO2. Secondary fluid CO2 inclusions in UHT quartz have a higher density than the primary inclusions, indicating a near-isobaric cooling path down to 700-750°C. In these conditions cordierite probably could steadily re-equilibrate at decreasing temperature while taking up more and more CO2, up to 3 wt.% around 700°C. The heat source for the UHTM in the Bakhuis Granulite belt is considered to be asthenospheric upwelling or mafic underplating, but mafic magmatism of identical age to the UHTM has not yet been found. One mafic intrusion was found to be around 20 Ma older than the UHTM, whereas in the SW of the belt numerous mafic intrusions formed around 70 Ma after UHTM

Utilisation of cardiac pacemakers over a 20-year period: Results from a nationwide pacemaker registry

The implantation of cardiac pacemakers has become a well-established therapy for conduction disorders and sinus node dysfunction. In many countries pacemaker registries have been initiated in order to collect information on patient characteristics, trends in numbers and the types of pacemakers used, to identify problematic devices, and for safety monitoring. For this utilisation study the Central Pacemaker Patients Registration (CPPR) from the Netherlands Pacemaker Registry Foundation (CPPR-SPRN) containing data collected for more than 20 years was used. During this period nearly 97,000 first pacemakers were implanted. Analyses show an increase in the rate of implanted devices. The change in pacemaker type from VVI to DDD, followed by biventricular stimulation, is reflected by the number of simultaneously implanted leads, which is partly a consequence of cardiac resynchronisation therapy. Our data demonstrate that indications for implantation and type of pacemaker are comparable with other European countries

Trends in service time of pacemakers in the Netherlands:A long-term nationwide follow-up study

Aims: After decades of experience and strongly improved technology, service time of pacemaker generators is expected to increase. To test this hypothesis, we conducted a retrospective review of a large cohort of patients with a pacemaker. Methods: We reviewed data collected between 1984 and 2006 in the first national Dutch pacemaker registry. This registry covered 96% of all generators implanted. We analysed the time of and reason for explantation of pacemaker generators. A 7-year follow-up interval after first implantation and following replacements was used to analyse changes over time. Results: During 22 years of data collection, nearly 97,000 first pacemaker generators were implanted. A total of 27,937 (22.4%) generators were explanted within a mean of 6.3 (standard deviation 3.3) years. Reasons for approximately 60% of these explantations were ` end of life' of the pacemaker generator or elective system change. Complications or failures such as infections and recalls accounted for approximately 20% of the explantations. For the remaining 20%, the reasons for explantation had not been registered. Conclusion: Despite progress in technology, a substantial proportion of pacemaker generators is explanted before its expected service time, with one in five generators being replaced due to technical failures, infections or other complications. Furthermore, the time interval between pacemaker implantation and explantation due to normal 'end of life' (battery EOL) decreased. Infections continue to rank highly as a cause for pacing system replacement, despite all current preventive measures

Greenhouse gas mitigation scenarios for major emitting countries Analysis of current climate policies and mitigation commitments: 2022 update

The 21st session of the Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC) held in 2015 adopted the Paris Agreement as the main international climate policy agreement for the post-2020 period (UNCCC, 2015). Parties to the Paris Agreement communicate Nationally Determined Contributions (NDCs), which are pledges containing their contribution to the challenge of reducing global emissions and keeping end-of-century warming below 1.5 °C. There is no yardstick to measure the adequacy of NDCs or the actual progress towards them. Therefore, to measure progress on the implementation of countries’ policies and targets is essential to make the Paris Agreement work. Most countries have updated their NDCs and adopted additional policies since the Paris Agreement came into force. The latest submitted targets are an improvement in comparison to the original ones but remain globally insufficient to curb global emissions (den Elzen et al., 2022a). Policies have also improved since 2015 but projections under currently adopted policies suggest emissions are still expected to increase up to 2030 (Nascimento et al., 2022). Despite these improvements, a global ambition gap exists between countries’ target and policies and the collective mitigation goals of the Paris Agreement. It is, therefore, crucial to continually track countries’ progress towards their NDCs and inform policymakers with up-to-date knowledge to ensure effective implementation of the ratcheting mechanism under the Paris Agreement. This report is prepared by NewClimate Institute, PBL Netherlands Environmental Assessment Agency and IIASA and presents a preliminary assessment of progress by 25 countries toward the achievement of the mitigation components of their 2030 targets. More specifically, the report provides an overview of projected greenhouse gas (GHG) emissions up to 2030, considering existing, and in some cases planned, climate and energy policies, and compares them with the emissions implied by the NDCs. In this year’s update, we compare updated NDC submissions to the original ones submitted between 2014 and 2016 to assess how countries’ NDCs compare to each other and whether current policies are sufficient to meet them

No accelerated arterial aging in relatively young women after preeclampsia as compared to normotensive pregnancy

IntroductionPreeclampsia, an endothelial disorder of pregnancy, predisposes to remote cardiovascular diseases (CVD). Whether there is an accelerated effect of aging on endothelial decline in former preeclamptic women is unknown. We investigated if the arterial aging regarding endothelial-dependent and -independent vascular function is more pronounced in women with a history of preeclampsia as compared to women with a history of solely normotensive gestation(s).MethodsData was used from the Queen of Hearts study (ClinicalTrials.gov Identifier NCT02347540); a large cross-sectional study on early detection of cardiovascular disease among young women (≥18 years) with a history of preeclampsia and a control group of low-risk healthy women with a history of uncomplicated pregnancies. Brachial artery flow-mediated dilation (FMD; absolute, relative and allometric) and sublingually administered nitroglycerine-mediated dilation (NGMD; absolute and relative) were measured using ultrasound. Cross-sectional associations of age with FMD and NGMD were investigated by linear regression. Models were adjusted for body mass index, smoking, antihypertensive drug use, mean arterial pressure, fasting glucose, menopausal state, family history of CVD and stress stimulus during measurement. Effect modification by preeclampsia was investigated by including an interaction term between preeclampsia and age in regression models.ResultsOf the 1,217 included women (age range 22–62 years), 66.0% had a history of preeclampsia and 34.0% of normotensive pregnancy. Advancing age was associated with a decrease in relative FMD and NGMD (unadjusted regression coefficient: FMD: −0.48%/10 years (95% CI:−0.65 to −0.30%/10 years), NGMD: −1.13%/10 years (−1.49 to −0.77%/10 years)) and increase in brachial artery diameter [regression coefficient = 0.16 mm/10 years (95% CI 0.13 to 0.19 mm/10 years)]. Similar results were found when evaluating FMD and NGMD as absolute increase or allometrically, and after confounder adjustments. These age-related change were comparable in former preeclamptic women and controls (p-values interaction ≥0.372). Preeclampsia itself was independently associated with consistently smaller brachial artery diameter, but not with FMD and NGMD.ConclusionIn young- to middle-aged women, vascular aging in terms of FMD and NGMD was not accelerated in women after preeclampsia compared to normotensive pregnancies, even though former preeclamptic women consistently have smaller brachial arteries

Air-Based Contactless Wafer Precision Positioning System

This paper presents the development of a contactless sensing system and the dynamic evaluation of an air-bearing-based precision wafer positioning system. The contactless positioning stage is a response to the trend seen in the high-tech industry, where the substrates are becoming thinner and larger to reduce the cost and increase the yield. Using contactless handling it is possible to avoid damage and contamination. The system works by floating the substrate on a thin film of air. A viscous traction force is created on the substrate by steering the airflow. A cascaded control design structure has been implemented on the contactless positioning system, where the inner loop controller (ILC) controls the actuator which steers the airflow and the outer loop controller (OLC) controls the position of the substrate by controlling the reference of the ILC. The dynamics of the ILC are evaluated and optimized for the performance of the positioning of the substrate. The vibration disturbances are also handled by the ILC. The bandwidth of the system has been improved to 300 Hz. For the OLC, a linear charge-coupled device has been implemented as a contactless sensor. The performance of the sensing system has been analysed. During control in steady-state, this resulted in a position error of the substrate of 12.9 μm RMS, which is a little more than two times the resolution. The bandwidth of the OLC is approaching 10 Hz