This study sought to derive age-, sex-, and ethnic-appropriate adult reference values for left atrial (LA) and left ventricular (LV) dimensions and volumes, LV mass, fractional shortening, and ...ejection fraction (EF) derived from geographically diverse population studies.
The current recommended reference values for measurements from echocardiography may not be suitable to the diverse world population to which they are now applied.
Population-based datasets of echocardiographic measurements from 22,404 adults without clinical cardiovascular or renal disease, hypertension, or diabetes were combined in an individual person data meta-analysis. Quantile regression was used to derive reference values at the 95th percentile (upper reference value URV) and fifth percentile (lower reference value LRV) of each measurement against age (treated as linear), separately within sex and ethnic groups.
The URVs for left ventricular end-diastolic volume (LVEDV), LV end-systolic volume, and LV stroke volume (SV) were highest in Europeans and lowest in South Asians. Important sex and ethnic differences remained after indexation by body surface area or height for these measurements, as well as for the LRV for SV. LVEDV and SV decreased with increasing age for all groups. Importantly, the LRV for EF differed by ethnicity; there was a clear apparent difference between Europeans and Asians. The URVs for LV end-diastolic diameter and LV end-systolic diameter were higher for Europeans than those for East Asian, South Asian, and African people, particularly among men. Similarly, the URVs for LA diameter and volume were highest for Europeans.
Sex- and/or ethnic-appropriate echocardiographic reference values are indicated for many measurements of LA and LV size, LV mass, and EF. Reference values for LV volumes and mass also differ across the age range.
In this study, we explored the effects of microbial activity on the evaporation of water from cores of a sandy soil under laboratory conditions. We applied treatments to stimulate microbial activity ...by adding different amounts of synthetic analogue root exudates. For comparison, we used soil samples without synthetic root exudates as control and samples treated with mercuric chloride to suppress microbial activity. Our results suggest that increasing microbial activity reduces the rate of evaporation from soil. Estimated diffusivities in soil with the largest amounts of added root exudates were one third of those estimated in samples where microbial activity was suppressed by adding mercuric chloride. We discuss the effect of our results with respect to water uptake by roots.
Highlights
We explored effects of microbial activity on the evaporation of water from cores of a sandy soil.
We found the effect of microbial activity on water release characteristic was small.
Increasing microbial activity reduced evaporation from soil, while microbial suppression increased it.
Effect of microbial activity on root water uptake was estimated to be equivalent to a change in soil structure.
Using natural language processing, it is possible to extract structured information from raw text in the electronic health record (EHR) at reasonably high accuracy. However, the accurate distinction ...between negated and non-negated mentions of clinical terms remains a challenge. EHR text includes cases where diseases are stated not to be present or only hypothesised, meaning a disease can be mentioned in a report when it is not being reported as present. This makes tasks such as document classification and summarisation more difficult. We have developed the rule-based EdIE-R-Neg, part of an existing text mining pipeline called EdIE-R (Edinburgh Information Extraction for Radiology reports), developed to process brain imaging reports, (https://www.ltg.ed.ac.uk/software/edie-r/) and two machine learning approaches; one using a bidirectional long short-term memory network and another using a feedforward neural network. These were developed on data from the Edinburgh Stroke Study (ESS) and tested on data from routine reports from NHS Tayside (Tayside). Both datasets consist of written reports from medical scans. These models are compared with two existing rule-based models: pyConText (Harkema et al. 2009. Journal of Biomedical Informatics 42(5), 839–851), a python implementation of a generalisation of NegEx, and NegBio (Peng et al. 2017. NegBio: A high-performance tool for negation and uncertainty detection in radiology reports. arXiv e-prints, p. arXiv:1712.05898), which identifies negation scopes through patterns applied to a syntactic representation of the sentence. On both the test set of the dataset from which our models were developed, as well as the largely similar Tayside test set, the neural network models and our custom-built rule-based system outperformed the existing methods. EdIE-R-Neg scored highest on F1 score, particularly on the test set of the Tayside dataset, from which no development data were used in these experiments, showing the power of custom-built rule-based systems for negation detection on datasets of this size. The performance gap of the machine learning models to EdIE-R-Neg on the Tayside test set was reduced through adding development Tayside data into the ESS training set, demonstrating the adaptability of the neural network models.
One of the most important functions of soil is to provide an environment for root growth. Ideally, roots will elongate with minimal impedance and acquire water and nutrients so that crops may grow to ...their full potential. In practice, physical stresses in the root environment restrict root growth: one of the most commonly-cited physical stresses that affect root growth is “mechanical impedance”. When soils are strong, because they are compact or dry, roots elongate more slowly and this in turn has a detrimental effect on plant growth. In this paper, we examine the relative importance of compaction and soil drying as factors that lead to strong soil. We measured soil strength with both a tensile test and a penetrometer. We compared pressures of rotating and fixed (non-rotating) penetrometers. The utility of the rotating penetrometer is that it is thought to give a resistance to penetration similar to that experienced by elongating plant roots. For three soils, we confirmed published work reporting that effective stress can be used to define a relationship between tensile strength and soil water status that is common for a range of soils. Then, for loamy sand and silty clay loam soils at two dry bulk densities, we considered the relationship between penetrometer pressure and effective stress at matric potentials greater than −100
kPa. We found that for both soils, penetrometer pressure increased with effective stress and for the loamy sand, but not the silty clay loam soil, penetrometer pressure increased with density for a given effective stress. To examine the relationship between soil density and effective stress more fully, we measured the penetrometer pressures of five soils at two densities following equilibration at −100
kPa. We suggest that effective stress can be used to predict penetrometer pressure (provided the soil is compressible) and therefore the resistance to root penetration offered by the soil. Rotation decreased penetrometer pressure in the soils tested. Data obtained from the rotating penetrometer suggests that relatively moist soils (matric potential as high as −100
kPa) can provide high mechanical impedance to root elongation.
Organic aerosols, a major constituent of fine particulate mass in megacities, can be directly emitted or formed from secondary processing of biogenic and anthropogenic volatile organic compound ...emissions. The complexity of volatile organic compound emission sources, speciation and oxidation pathways leads to uncertainties in the key sources and chemistry leading to formation of organic aerosol in urban areas. Historically, online measurements of organic aerosol composition have been unable to resolve specific markers of volatile organic compound oxidation, while offline analysis of markers focus on a small proportion of organic aerosol and lack the time resolution to carry out detailed statistical analysis required to study the dynamic changes in aerosol sources and chemistry. Here we use data collected as part of the joint UK-China Air Pollution and Human Health (APHH-Beijing) collaboration during a field campaign in urban Beijing in the summer of 2017 alongside laboratory measurements of secondary organic aerosol from oxidation of key aromatic precursors (1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, propyl benzene, isopropyl benzene and 1-methyl naphthalene) to study the anthropogenic and biogenic contributions to organic aerosol. For the first time in Beijing, this study applies positive matrix factorisation to online measurements of organic aerosol composition from a time-of-flight iodide chemical ionisation mass spectrometer fitted with a filter inlet for gases and aerosols (FIGAERO-ToF-I-CIMS). This approach identifies the real-time variations in sources and oxidation processes influencing aerosol composition at a near-molecular level. We identify eight factors with distinct temporal variability, highlighting episodic differences in OA composition attributed to regional influences and in situ formation. These have average carbon numbers ranging from C
-C
and can be associated with oxidation of anthropogenic aromatic hydrocarbons alongside biogenic emissions of isoprene, α-pinene and sesquiterpenes.
Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. ...Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood.
Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained from study investigators. Results were provided by all study investigators in a standard format and pooled using random-effects meta-analyses. 19 studies were included in the review. Total sample sizes in meta-analyses ranged from N = 17,215 for chair rise time to N = 1,061,855 for grip strength. Although heterogeneity was detected, there was consistent evidence in age adjusted models that lower childhood SEP was associated with modest reductions in physical capability levels in adulthood: comparing the lowest with the highest childhood SEP there was a reduction in grip strength of 0.13 standard deviations (95% CI: 0.06, 0.21), a reduction in mean walking speed of 0.07 m/s (0.05, 0.10), an increase in mean chair rise time of 6% (4%, 8%) and an odds ratio of an inability to balance for 5s of 1.26 (1.02, 1.55). Adjustment for the potential mediating factors, adult SEP and body size attenuated associations greatly. However, despite this attenuation, for walking speed and chair rise time, there was still evidence of moderate associations.
Policies targeting socioeconomic inequalities in childhood may have additional benefits in promoting the maintenance of independence in later life.
Soil compaction has deleterious effects on soil physical properties, which can affect plant growth, but some soils are inherently resilient, whereby they may recover following removal of the stress. ...We explored aspects of soil physical resilience in a field-based experiment. We subjected three soils of different texture, sown with winter wheat or remaining fallow, to a compaction event. We then monitored soil strength, as a key soil physical property, over the following 16 months. We were also interested in the associated interactions with crop growth and the microbial community. Compaction had a considerable and sustained effect in a sandy loam and a sandy clay loam soil, resulting in an increase in strength and decreased crop yields. By contrast compaction had little effect on a clay soil, perhaps due initially to the buoyancy effect of pore water pressure. Fallow clay soil did have a legacy of the compaction event at depth, however, suggesting that it was the actions of the crop, and rooting in particular, that maintained smaller strengths in the cropped clay soil rather than other physical processes. Compaction generally did not affect microbial communities, presumably because they occupy pores smaller than those affected by compaction. That the clay soil was able to supply the growing crop with sufficient water whilst remaining weak enough for root penetration was a key finding. The clay soil was therefore deemed to be much more resilient to the compaction stress than the sandy loam and sandy clay loam soils.
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