4,458 research outputs found
The glacial cycles and cosmic rays
The cause of the glacial cycles remains a mystery. The origin is widely
accepted to be astronomical since paleoclimatic archives contain strong
spectral components that match the frequencies of Earth's orbital modulation.
Milankovitch insolation theory contains similar frequencies and has become
established as the standard model of the glacial cycles. However, high
precision paleoclimatic data have revealed serious discrepancies with the
Milankovitch model that fundamentally challenge its validity and re-open the
question of what causes the glacial cycles. We propose here that the ice ages
are initially driven not by insolation cycles but by cosmic ray changes,
probably through their effect on clouds. This conclusion is based on a wide
range of evidence, including results presented here on speleothem growth in
caves in Austria and Oman, and on a record of cosmic ray flux over the past 220
kyr obtained from the 10Be composition of deep-ocean sediments
Exercise-induced asthma in a group of South African schoolchildren during physical education classes
Objectives. The study was conducted to ascertain whether physical education teachers, using a peak flow meter, could reliably screen for exercise-induced asthma (EIA) in children during free running.Design, setting and subjects. The study was conducted using a convenience sample of male pupils between the ages of 12 and 18 years. They were tested with a peak flow meter for peak expiratory flow rate (PEFR) and with a flow-volume curve for forced expiratory flow in 1 second (FEV1) before and 10 minutes after a self-paced free running test during physical education classes. Testing was undertaken by teachers using the peak flow meter and by a medical doctor using a flow-volume curve.Results. Using a 10% decrease in flow parameters (PEFR and FEV1), teachers detected EIA in 14.9% of pupils and the doctor detected EIA in 21.7% of pupils.Conclusion. We conclude that EIA is common and that teachers using a peak flow meter can detect EIA and thus screen for it; they do, however, underestimate the true magnitude of the problem
Estimating the health benefits of progeny extraction units as a means of reducing exposure to radon
Radon exposure to the general public can be reduced by preventing entry of radon gas into buildings using a passive radon-proof membrane or an active sump and pump system. However, a significant majority of the radiation dose delivered is from the decay products of radon rather than from the gas itself. These decay products (also referred to as progeny) are present in indoor air, with an equilibrium factor – a measure of the ratio of progeny to radon gas – of between 0.4 to 0.5. As a result, systems which extract radon progeny from the air by filtering have been promoted as means of reducing exposure to the general population.
The European Community Radon Software (ECRS) offers a means of estimating lung-cancer risk associated with an individual’s exposure to radon, and includes the possibility of estimating the health risk from different proportions of radon gas and its progeny by varying the value of the Equilibrium Factor. This software was used to estimate the health benefits associated with reduced decay products in differing concentrations of radon gas. The results were compared to health benefits expected if the risk was reduced by the standard method of reducing the radon gas concentration below the Action Level, which in the UK is 200 Bq·m-3 for domestic properties.
These calculations showed that there is the potential for efficient extraction units to provide the necessary dose and risk reduction where initial average radon gas concentrations are up to 800 Bq·m-3. However, above 1000 Bq·m-3, such systems cannot reduce the health risk sufficiently to reach levels comparable to those resulting from radon gas reduction to below the Action Leve
Bodyspace at the pub: sexual orientations and organizational space
In this article we argue that sexuality is not only an undercurrent of service environments, but is integral to the way that these workspaces are experienced and negotiated. Through drawing on Sara Ahmed’s (2006a) ‘orientation’ thesis, we develop a concept of ‘bodyspace’ to suggest that individuals understand, shape and make meaning of work spaces through complex sexually-orientated negotiations. Presenting analysis from a study of UK pubs, we explore bodyspace in the lived experience of workplace sexuality through three elements of orientation: background; bodily dwelling; and lines of directionality. Our findings show how organizational spaces afford or mitigate possibilities for particular bodies, which simultaneously shape expectations and experiences of sexuality at work. Bodyspace therefore provides one way of exposing the connection between sexual ‘orientation’ and the lived experience of service sector work
Children’s Reading of Sublexical Units in Years Three to Five: A Combined Analysis of Eye-Movements and Voice Recording
Purpose
Children progress from making grapheme–phoneme connections to making grapho-syllabic connections before whole-word connections during reading development (Ehri, 2005a). More is known about the development of grapheme–phoneme connections than is known about grapho-syllabic connections. Therefore, we explored the trajectory of syllable use in English developing readers during oral reading.
Method
Fifty-one English-speaking children (mean age: 8.9 years, 55% females, 88% monolinguals) in year groups three, four, and five read aloud sentences with an embedded target word, while their eye movements and voices were recorded. The targets contained six letters and were either one or two syllables.
Result
Children in grade five had shorter gaze duration, shorter articulation duration, and larger spatial eye-voice span (EVS) than children in grade four. Children in grades three and four did not significantly differ on these measures. A syllable number effect was found for gaze duration but not for articulation duration and spatial EVS. Interestingly, one-syllable words took longer to process compared to two-syllable words, suggesting that more syllables may not always signify greater processing difficulty.
Conclusion
Overall, children are sensitive to sublexical reading units; however, due to sample and stimuli limitations, these findings should be interpreted with caution and further research conducted
Interpreting short and medium exposure etched-track radon measurements to determine whether an action level could be exceeded
Radon gas is naturally occurring, and can concentrate in the built environment. It is radioactive and high concentration levels within buildings, including homes, have been shown to increase the risk of lung cancer in the occupants. As a result, several methods have been developed to measure radon. The long-term average radon level determines the risk to occupants, but there is always pressure to complete measurements more quickly, particularly when buying and selling the home. For many years, the three-month exposure using etched-track detectors has been the de facto standard, but a decade ago, Phillips et al. (2003), in a DEFRA funded project, evaluated the use of 1-week and 1-month measurements. They found that the measurement methods were accurate, but the challenge lay in the wide variation in radon levels - with diurnal, seasonal, and other patterns due to climatic factors and room use. In the report on this work, and in subsequent papers, the group proposed methodologies for 1-week, 1-month and 3-month measurements and their interpretation. Other work, however, has suggested that 2-week exposures were preferable to 1-week ones. In practice, the radon remediation industry uses a range of exposure times, and further guidance is required to help interpret these results. This paper reviews the data from this study and a subsequent 4-year study of 4 houses, re-analysing the results and extending them to other exposures, particularly for 2-week and 2-month exposures, and provides comprehensive guidance for the use of etched-track detectors, the value and use of Seasonal Correction Factors (SCFs), the uncertainties in short and medium term exposures and the interpretation of results
Characteristics of Marri (Corymbia calophylla) fruits in relation to the foraging behaviour of the Forest Red-tailed Black Cockatoo (Calyptorhynchus banksii naso)
Forest Red-tailed Black Cockatoos (Calyptorhynchus banksii naso) feed predominantly on seeds of the eucalypt Marri (Corymbia calophylla) and often only from specific feed trees. There was no difference between wet weight of fruits from feed (24.1 ± 1.72 g) and non-feed trees (23.2 ± 1.57 g), but trees from which Forest Red-tailed Black Cockatoos fed had a significantly higher seed number per fruit (3.9 ± 0.18), a greater individual dry seed weight (0.10 ± 0.003 g) and total seed weight per fruit (0.39 ± 0.02 g), and a higher ratio of total seed dry weight to fruit wet weight (0.02 ± 0.001) compared with non-feed trees (3.1 ± 0.20 seeds per fruit; 0.09 ± 0.005 g individual seed dry weight; 0.29 ± 0.020 g total seed dry weight per fruit; 0.013 ± 0.001 ratio of total seed dry weight to fruit wet weight). Discriminate analysis had a limited capacity to predict Marri use by Forest Red-tailed Black Cockatoos, correctly classifying about 70 % of feed trees. Seed number and total seed mass were the best fruit characteristics for the prediction of tree type. We conclude that Forest Red-tailed Black Cockatoos selectively forage from trees with fruits that have a high seed yield, but the method by which the cockatoos select these trees is unclear
Dual input stream transformer for eye-tracking line assignment
We introduce a novel Dual Input Stream Transformer (DIST) for the challenging
problem of assigning fixation points from eye-tracking data collected during
passage reading to the line of text that the reader was actually focused on.
This post-processing step is crucial for analysis of the reading data due to
the presence of noise in the form of vertical drift. We evaluate DIST against
nine classical approaches on a comprehensive suite of nine diverse datasets,
and demonstrate DIST's superiority. By combining multiple instances of the DIST
model in an ensemble we achieve an average accuracy of 98.5\% across all
datasets. Our approach presents a significant step towards addressing the
bottleneck of manual line assignment in reading research. Through extensive
model analysis and ablation studies, we identify key factors that contribute to
DIST's success, including the incorporation of line overlap features and the
use of a second input stream. Through evaluation on a set of diverse datasets
we demonstrate that DIST is robust to various experimental setups, making it a
safe first choice for practitioners in the field.Comment: This work has been submitted to the IEEE Transactions on pattern
analysis and machine intelligence for possible publication. Copyright may be
transferred without notice, after which this version may no longer be
accessible. Code will be published after publicatio
- …