Investigation of the discrete effects of suction in large scale arrays for Laminar flow control

An experimental investigation of the destabilising effects of discrete suction perforations for laminar flow control applications was performed. This research was aimed at investigation of the flow physics of large arrays of discrete perforated suction arrays in globally two-dimensional flows. This research also investigated the effect of varying perforation size, free-stream velocity and suction volume flow rate on the amplification and attenuation of excited travelling waves in a two-dimensional laminar flow. It was found that instead of creating local instabilities that destabilise all frequencies, strong suction had the effect of introducing low frequency disturbances while attenuating naturally produced and excited travelling waves for all test cases considered. If the suction was sufficiently strong these low frequency disturbances would appear to dominate over the stabilising effect of suction (on the natural and excited modes). Possible explanations for these disturbances include viscous or acoustic disturbances located within the suction system. Future experiments will attempt to isolate the effect of the plenums to determine if this is the source of these low frequency disturbances

B-Type Natriuretic Peptide Assessment in Patients Undergoing Revascularization for Left Main Coronary Artery Disease

BACKGROUND: Elevated B-type natriuretic peptide (BNP) is reflective of impaired cardiac function and is associated with worse prognosis among patients with coronary artery disease (CAD). We sought to assess the association between baseline BNP, adverse outcomes, and the relative efficacy of percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) in patients with left main CAD. METHODS: The EXCEL trial (Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) randomized patients with left main CAD and low or intermediate SYNTAX scores (Synergy Between PCI With TAXUS and Cardiac Surgery) to PCI with everolimus-eluting stents versus CABG. The primary end point was the composite of all-cause death, myocardial infarction, or stroke. We used multivariable Cox proportional hazards regression to assess the associations between normal versus elevated BNP (≥100 pg/mL), randomized treatment, and the 3-year risk of adverse events. RESULTS: BNP at baseline was elevated in 410 of 1037 (39.5%) patients enrolled in EXCEL. Patients with elevated BNP levels were older and more frequently had additional cardiovascular risk factors and lower left ventricular ejection fraction than those with normal BNP, but had similar SYNTAX scores. Patients with elevated BNP had significantly higher 3-year rates of the primary end point (18.6% versus 11.7%; adjusted hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.16-2.28; P=0.005) and higher mortality (11.5% versus 3.9%; adjusted HR, 2.49; 95% CI, 1.48-4.19; P=0.0006), both from cardiovascular and noncardiovascular causes. In contrast, there were no significant differences in the risks of myocardial infarction, stroke, ischemia-driven revascularization, stent thrombosis, graft occlusion, or major bleeding. A significant interaction ( Pinteraction=0.03) was present between elevated versus normal BNP and treatment with PCI versus CABG for the adjusted risk of the primary composite end point at 3 years among patients with elevated BNP (adjusted HR for PCI versus CABG, 1.54; 95% CI, 0.96-2.47) versus normal BNP (adjusted HR, 0.74; 95% CI, 0.46-1.20). This interaction was stronger when log(BNP) was modeled as a continuous variable ( Pinteraction=0.002). CONCLUSIONS: In the EXCEL trial, elevated baseline BNP levels in patients with left main CAD undergoing revascularization were independently associated with long-term mortality but not nonfatal adverse ischemic or bleeding events. The relative long-term outcomes after PCI versus CABG for revascularization of left main CAD may be conditioned by the baseline BNP level. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01205776

The Atacama Cosmology Telescope: A Catalog of >4000 Sunyaev–Zel’dovich Galaxy Clusters

We present a catalog of 4195 optically confirmed Sunyaev–Zel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 × 1014 M⊙, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2farcm4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Age at first birth in women is genetically associated with increased risk of schizophrenia

Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

A Meta-Methods Analysis of Academics' Challenges Affecting Research Productivity During COVID-19: Insights from a South African University

Research productivity is an essential metric for universities. Therefore, the purpose of this meta-methods research study was to examine challenges experienced by academics at Stellenbosch University that hinder their research productivity during the COVID-19 pandemic. A convenience sample of 248 academics completed an online questionnaire. A qualitative analysis of the open-ended responses revealed five themes that characterised the extent that the COVID-19 pandemic impacted the research productivity of academics: Online Teaching, Increase in Research Productivity, No Difference to Research Productivity, Reduced Research Productivity, and No Research Productivity. A mixed methods analysis, namely, descriptive-based quantitizing, revealed that only 25% of academics were not adversely affected by online teaching in terms of research productivity. Approximately two thirds of the academics experienced either a reduction in productivity or reported no research productivity at all. Inferential-based quantitizing revealed that, compared to academics who reported an increase in productivity, academics who reported undertaking no research productivity at all tended to be women, not to hold a professor position, not to have a doctorate degree, to have less experience as academics, to have access at home to a tablet, but not to have access at home to cellphone data. Implications of these findings are discussed

Experimental studies of the arc chamber short circuit failure mechanism on the DIII-D neutral beam system

Here we report on efforts to improve performance and longevity of the Neutral Beam Injection (NBI) system by initiating a R&D program aimed at studying the most common failure mechanism for the ion sources. To this end a filament driven plasma chamber has been constructed with plasma parameters similar to the arc chamber of NBI ion sources. A preliminary report of an investigation into the most common failure is presented here: The failure mechanism observed during helium operations on DIII-D is the result of electrical breakdown of the insulation material that separates the filament plates from the anode. The fault is reproduced in a table top experiment analogous to the DIII-D NBI ion source in key parameters and proposals for amelioration of the issue are discussed

Hydrothermal Formation Of Clay-carbonate Alteration Assemblages In The Nili Fossae Region Of Mars

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has returned observations of the Nili Fossae region indicating the presence of Mg-carbonate in small (<10km sq2), relatively bright rock units that are commonly fractured (Ehlmann et al., 2008b). We have analyzed spectra from CRISM images and used co-located HiRISE images in order to further characterize these carbonate-bearing units. We applied absorption band mapping techniques to investigate a range of possible phyllosilicate and carbonate minerals that could be present in the Nili Fossae region. We also describe a clay-carbonate hydrothermal alteration mineral assemblage in the Archean Warrawoona Group of Western Australia that is a potential Earth analog to the Nili Fossae carbonate-bearing rock units. 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Brazilian Analog For Ancient Marine Environments On Mars

[No abstract available]8936329330Bibring, J., Mars surface diversity as revealed by the OMEGA/Mars Express observations (2005) Science, 307, pp. 1576-1581Christensen, P.R., Detection of crystalline hematite mineralization on Mars by the Thermal Emission Spectrometer. Evidence for near-surface water (2000) J. Geophys. Res, 105, pp. 9623-9642Connerney, J.E.P., Magnetic lineations in the ancient crust of Mars (1999) Science, 284, pp. 794-798Crowley, J.K., Spectral diversity of terrestrial banded iron formations and associated rocks: Implications for Mars remote sensing (2008) Lunar Planet Sci, 39, p. 1263Dalstra, H., Guedes, S., Giant hydrothermal hematite deposits with Mg-Fe metasomatism: A comparison of the Carajas, Hamersley, and other iron ores (2004) Econ. Geol, 99, pp. 1793-1800Fallacaro, A., Calvin, W.M., Spectral properties of Lake Superior banded iron formation: Application to Martian hematite deposits (2006) Astrobiology, 6, pp. 563-580Klein, C., Some Precambrian banded-iron formations (BIFs) from around the world: Their age, geologic setting, mineralogy, metamorphism, geochemistry, and origin (2005) Am. Mineral, 90, pp. 1473-1499Klein, C., Ladeira, E.A., Petrography and geochemistry of the least altered banded iron-formation of the Archean Carajas Formation, northern Brazil (2002) Econ. Geol, 97, pp. 643-651Squyres, S.W., In situ evidence for an ancient aqueous environment at Meridiani Planum, Mars (2004) Science, 306, pp. 1709-1714Trendall, A.F., The significance of iron-formation in the Precambrian stratigraphic record (2002) Spec. Publ. Int. Assoc. Sedimentol, 33, pp. 33-66Trendall, A.F., Basei, M.A.S., de Laeter, J.R., Nelson, D.R., Ion microprobe zircon, U-Pb results from the Carajas area of the Amazon craton (1998) J. S. Am. Earth Sci, 11, pp. 265-27