143 research outputs found
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Terrestrial carbon isotope stratigraphy and mammal turnover during post-PETM hyperthermals in the Bighorn Basin, Wyoming, USA
Paleogene hyperthermals, including the Paleocene–Eocene Thermal Maximum (PETM) and several other smaller events, represent global perturbations to Earth’s climate system and are characterized by warmer temperatures, changes in floral and faunal communities, and hydrologic changes. These events are identified in the geologic record globally by negative carbon isotope excursions (CIEs), resulting from the input of isotopically light carbon into Earth’s atmosphere. Much about the causes and effects of hyperthermals remains uncertain, including whether all hyperthermals were caused by the same underlying processes, how biotic effects scale with the magnitude of hyperthermals, and why CIEs are larger in paleosol carbonates relative to marine records. Resolving these questions is crucial for a full understanding of the causes of hyperthermals and their application to future climate scenarios. The primary purpose of this study was to identify early Eocene hyperthermals in the Fifteenmile Creek area of the south-central Bighorn Basin, Wyoming, USA. This area preserves a sequence of fluvial floodplain sedimentary rocks containing paleosol carbonates and an extensive record of fossil mammals. Previous analysis of faunal assemblages in this area revealed two pulses of mammal turnover and changes in diversity interpreted to correlate with the ETM2 and H2 hyperthermals that follow the PETM. This was, however, based on long-distance correlation of the fossil record in this area with chemostratigraphic records from elsewhere in the basin.
We present new carbon isotope stratigraphies using micrite δ13C values from paleosol carbonate nodules preserved in and between richly fossiliferous mammal localities at Fifteenmile Creek to identify the stratigraphic positions of ETM2 and H2. Carbon isotope results show that the ETM2 and H2 hyperthermals, and possibly the subsequent I1 hyperthermal, are recorded at Fifteenmile Creek. ETM2 and H2 overlap with the two previously recognized pulses of mammal turnover. The CIEs for these hyperthermals are also somewhat smaller in magnitude than in more northerly Bighorn Basin records. We suggest that basin-wide differences in soil moisture and/or vegetation could contribute to variable CIE amplitudes in this and other terrestrial records
"The daily grunt": middle class bias and vested interests in the 'Getting in Early' and 'Why Can't They Read?' reports.
It is a long-standing and commonly held belief in the UK and elsewhere that the use of elite forms of language reflects superior intellect and education. Expert opinion from sociolinguistics, however, contends that such a view is the result of middle-class bias and cannot be scientifically justified. In the 1960s and 1970s,such luminaries as Labov (1969) and Trudgill (1975) were at pains to point out to educationalists, with some success, that this 'deficit 'view of working-class children's communicative competence is not a helpful one. However, a close reading of recent think-tank reports and policy papers on language and literacy teaching in schools reveals that the linguistic deficit hypothesis has resurfaced and is likely to influence present-day educational policy and practice. In this paper I examine in detail the findings, claims and recommendations of the reports and I argue that they are biased, poorly researched and reflect the vested interests of certain specialist groups, such as speech and language therapists and companies who sell literacy materials to schools. I further argue that we need to, once again, inject the debate with the social dimensions of educational failure, and we need to move away from the pathologisation of working-class children's language patterns
Impact of a 6-wk olive oil supplementation in healthy adults on urinary proteomic biomarkers of coronary artery disease, chronic kidney disease, and diabetes (types 1 and 2): a randomized, parallel, controlled, double-blind study
Background: Olive oil (OO) consumption is associated with cardiovascular disease prevention because of both its oleic acid and phenolic contents. The capacity of OO phenolics to protect against low-density lipoprotein (LDL) oxidation is the basis for a health claim by the European Food Safety Authority. Proteomic biomarkers enable an early, presymptomatic diagnosis of disease, which makes them important and effective, but understudied, tools for primary prevention.
Objective: We evaluated the impact of supplementation with OO, either low or high in phenolics, on urinary proteomic biomarkers of coronary artery disease (CAD), chronic kidney disease (CKD), and diabetes.
Design: Self-reported healthy participants (n = 69) were randomly allocated (stratified block random assignment) according to age and body mass index to supplementation with a daily 20-mL dose of OO either low or high in phenolics (18 compared with 286 mg caffeic acid equivalents per kg, respectively) for 6 wk. Urinary proteomic biomarkers were measured at baseline and 3 and 6 wk alongside blood lipids, the antioxidant capacity, and glycation markers.
Results: The consumption of both OOs improved the proteomic CAD score at endpoint compared with baseline (mean improvement: –0.3 for low-phenolic OO and −0.2 for high-phenolic OO; P < 0.01) but not CKD or diabetes proteomic biomarkers. However, there was no difference between groups for changes in proteomic biomarkers or any secondary outcomes including plasma triacylglycerols, oxidized LDL, and LDL cholesterol.
Conclusion: In comparison with low-phenolic OO, supplementation for 6 wk with high-phenolic OO does not lead to an improvement in cardiovascular health markers in a healthy cohort. This trial was registered at www.controlled-trials.com as ISRCTN93136746
Spitzer observations of hydrogen deuteride
We report the detection of interstellar hydrogen deuteride (HD) toward the
supernova remnant IC443, and the tentative detection of HD toward the Herbig
Haro objects HH54 and HH7 and the star forming region GGD37 (Cepheus A West).
Our detections are based upon spectral line mapping observations of the R(3)
and R(4) rotational lines of HD, at rest wavelengths of 28.502 and 23.034
micron respectively, obtained using the Infrared Spectrograph onboard the
Spitzer Space Telescope. The HD R(4)/R(3) line intensity ratio promises to be a
valuable probe of the gas pressure in regions where it can be observed. The
derived HD/H2 abundance ratios are 1.19(+0.35/-0.24)E-5, 1.80(+0.54/-0.32)E-5,
and 1.41(+0.46/-0.33)E-5 respectively (68.3% confidence limits, based upon
statistical errors alone) for IC443 (clump C), HH54, and HH7. If HD is the only
significant reservoir of gas-phase deuterium in these sources, the inferred
HD/H2 ratios are all consistent with a gas-phase elemental abundance
[n(D)/n(H)](gas) ~ 7.5E-6, a factor 2 - 3 below the values obtained previously
from observations of atomic deuterium in the local bubble and the Galactic
halo. However, similarly low gas-phase deuterium abundances have been inferred
previously for molecular gas clouds in the Orion region, and in atomic clouds
along sight-lines within the Galactic disk to stars more distant than 500 pc
from the Sun.Comment: 12 pages, including 5 figures. Accepted for publication in ApJ
Letter
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Temperature equilibration in strongly coupled plasma
A laser-driven experiment investigating electron-ion equilibration in strongly coupled plasma was performed in 1995. At that time, standard estimates for the electron-ion equilibration time were two-to-three orders of magnitude faster than observed experimentally. As a result, the electron-ion equilibration time was taken as a fitting parameter to understand the experimental results. Based upon guidance from nonequilibrium molecular dynamics mixture calculations 121 and comparison with strongly coupled resistivity experiments, we have developed a consistent binary collision model to understand the electron-ion equilibration experiment. The model has been implemented in a newly developed multi-species, multi-temperature physics code, which was used for simulation of the experiment. The resulting electron-ion exchange rate is close to the experiment, which is about three orders-of-magnitude slower than given by standard estimates, most of which is the result of a modified coulomb logarithm
Urinary Proteomics to Support Diagnosis of Stroke
Accurate diagnosis in suspected ischaemic stroke can be difficult. We explored the urinary proteome in patients with stroke (n = 69), compared to controls (n = 33), and developed a biomarker model for the diagnosis of stroke. We performed capillary electrophoresis online coupled to micro-time-of-flight mass spectrometry. Potentially disease-specific peptides were identified and a classifier based on these was generated using support vector machine-based software. Candidate biomarkers were sequenced by liquid chromatography-tandem mass spectrometry. We developed two biomarker-based classifiers, employing 14 biomarkers (nominal p-value <0.004) or 35 biomarkers (nominal p-value <0.01). When tested on a blinded test set of 47 independent samples, the classification factor was significantly different between groups; for the 35 biomarker model, median value of the classifier was 0.49 (−0.30 to 1.25) in cases compared to −1.04 (IQR −1.86 to −0.09) in controls, p<0.001. The 35 biomarker classifier gave sensitivity of 56%, specificity was 93% and the AUC on ROC analysis was 0.86. This study supports the potential for urinary proteomic biomarker models to assist with the diagnosis of acute stroke in those with mild symptoms. We now plan to refine further and explore the clinical utility of such a test in large prospective clinical trials
Coronary artery calcium screening: current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging
Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importance of standardization of coronary artery calcium measurements by multi-detector CT is discussed
Erratum to: Methods for evaluating medical tests and biomarkers
[This corrects the article DOI: 10.1186/s41512-016-0001-y.]
Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.
Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant
Sensitivity of SARS-CoV-2 B.1.1.7 to mRNA vaccine-elicited antibodies
SARS-CoV-2 transmission is uncontrolled in many parts of the world, compounded in some areas by higher transmission potential of the B1.1.7 variant1 now reported in 94 countries. It is unclear whether responses to SARS-CoV-2 vaccines based on the prototypic strain will be impacted by mutations found in B.1.1.7. Here we assessed immune responses following vaccination with mRNA-based vaccine BNT162b22. We measured neutralising antibody responses following first and second immunisations using pseudoviruses expressing the wild-type Spike protein or the 8 amino acid mutations found in the B.1.1.7 spike protein. The vaccine sera exhibited a broad range of neutralising titres against the wild-type pseudoviruses that were modestly reduced against B.1.1.7 variant. This reduction was also evident in sera from some convalescent patients. Decreased B.1.1.7 neutralisation was also observed with monoclonal antibodies targeting the N-terminal domain (9 out of 10), the RBM (5 out of 31), but not in RBD neutralising mAbs binding outside the RBM. Introduction of the E484K mutation in a B.1.1.7 background to reflect a newly emergent Variant of Concern (VOC 202102/02) led to a more substantial loss of neutralising activity by vaccine-elicited antibodies and mAbs (19 out of 31) over that conferred by the B.1.1.7 mutations alone. E484K emergence on a B.1.1.7 background represents a threat to the vaccine BNT162b
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