5,180 research outputs found
On the fine structure of medium energy electron fluxes in the auroral zone and related effects in the ionospheric D-region
This study is based on measurements of trapped and precipitated electrons of energy >30 keV and >100 keV observed by
polar orbiting environmental satellites during overpasses of the imaging riometer at Kilpisjärvi, Finland.
The satellites are in sun-synchronous orbits of about 850 km altitude, recording the electron fluxes at 2-s time resolution.
The riometer measures the radiowave absorption at 38.2 MHz, showing the spatial pattern within a 240 km field of view.
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The analysis has focussed on two areas.
Having found a close correlation between the radiowave absorption and the medium-energy electron fluxes during satellite overpasses,
empirical relationships are derived, enabling one quantity to be predicted from the other for three sectors of local time.
It is shown that small-scale variations observed during a pass are essentially spatial rather than temporal.
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Other properties, such as the spectra and the relation between precipitated and trapped components, are also considered in the light of the theory
of pitch angle scattering by VLF waves.
It is found that the properties and behaviour depend strongly on the time of day.
In the noon sector, the precipitated and trapped fluxes are highly correlated through a square law relationship
Small carbon chains in circumstellar envelopes
Observations were made for a number of carbon-rich circumstellar envelopes
using the Phoenix spectrograph on the Gemini South telescope to determine the
abundance of small carbon chain molecules. Vibration-rotation lines of the
antisymmetric stretch of C near 2040 cm (4.902 m)
have been used to determine the column density for four carbon-rich
circumstellar envelopes: CRL 865, CRL 1922, CRL 2023 and IRC +10216. We
additionally calculate the column density of C for IRC +10216, and
provide an upper limit for 5 more objects. An upper limit estimate for the
C column density is also provided for IRC+10216. A comparison of these
column densities suggest a revision to current circumstellar chemical models
may be needed
Clustering and Micro-immiscibility in Alcohol-Water Mixtures: Evidence from Molecular Dynamics Simulations
We have investigated the hydrogen-bonded structures in liquid methanol and a
7:3 mole fraction aqueous solution using classical Molecular Dynamics
simulations at 298K and ambient pressure. We find that, in contrast to recent
predictions from X-ray emission studies, the hydrogen-bonded structure in
liquid methanol is dominated by chain and small ring structures. In the
methanol-rich solution, we find evidence of micro-immiscibility, supporting
recent conclusions derived from neutron diffraction data.Comment: 5 pages, 4 figure
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Access to healthcare for people seeking and refused asylum in Great Britain: a review of evidence
This research report is a review of evidence looking at the barriers people seeking or refused asylum face in trying to access healthcare services in the UK, and what may help them to do so more easily.
This report, and the partner report on lived experiences (https://www.equalityhumanrights.com/en/publication-download/lived-experiences-access-healthcare-people-seeking-and-refused-asylum), will be of interest to people who play an important role in delivering healthcare and related support services to people seeking or refused asylum.
We have also made recommendations for what changes are needed (https://www.equalityhumanrights.com/en/publication-download/making-sure-people-seeking-and-refused-asylum-can-access-healthcare-what-needs) to make sure that people seeking and refused asylum have full enjoyment of their right to health.
This review was carried out by Imperial College London, with primary data provided by Doctors of the World UK
Mobilising communities to address alcohol harm : an Alcohol Health Champion approach
In this article, Cathy Ure et al. look at engaging communities in order to reduce alcohol harms. By training Alcohol Health Champions, individuals can support vulnerable friends and family, and work within their communities to influence policy and promote change
The estimation of D-region electron densities from riometer data
International audienceAt high latitude the hard electron precipitation associated with auroral activity is a major source of ionization for the D-region, one consequence being the absorption of radio waves. Direct measurements of the D-region electron density are not readily available, however. This paper investigates the relationship between the electron density at altitudes between 100 and 70 km and the total radio absorption observed with a riometer, with a view to using the latter to predict the former. Tables are given of the median electron density corresponding to 1 dB absorption at 27.6 MHz for each hour of the day, and it is shown that at certain heights the estimates will be accurate to within a factor of 1.6 on 50% of the occasions. A systematic variation with time of day is probably associated with a progressive hardening of the typical electron spectrum during the morning hours. There is also evidence for a seasonal effect possibly due to seasonal variations of the mesosphere
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The lived experiences of access to healthcare for people seeking and refused asylum
This research aims to explore the lived experiences of accessing healthcare among people currently seeking asylum and those who have had their claim for asylum refused, as well as the experiences of health service providers working with these communities.
It examines the extent to which people are able to exercise their rights to access healthcare. It looks at the differences between those currently in the asylum system and those who have had their claim refused in England, Scotland and Wales.
This report, and the partner report providing a review of evidence (https://www.equalityhumanrights.com/en/publication-download/access-healthcare-people-seeking-and-refused-asylum-great-britain-review), will be of interest to people who play an important role in delivering healthcare and related support services to people seeking or refused asylum.
We have also made recommendations for what changes are needed (https://www.equalityhumanrights.com/en/publication-download/making-sure-people-seeking-and-refused-asylum-can-access-healthcare-what-needs) to make sure that people seeking and refused asylum have full enjoyment of their right to health.
This report was produced in collaboration with Imperial College London and Doctors of the World UK
The measurement of household socio-economic position in tuberculosis prevalence surveys: a sensitivity analysis.
OBJECTIVE: To assess the robustness of socio-economic inequalities in tuberculosis (TB) prevalence surveys. DESIGN: Data were drawn from the TB prevalence survey conducted in Lusaka Province, Zambia, in 2005-2006. We compared TB socio-economic inequalities measured through an asset-based index (Index 0) using principal component analysis (PCA) with those observed using three alternative indices: Index 1 and Index 2 accounted respectively for the biases resulting from the inclusion of urban assets and food-related variables in Index 0. Index 3 was built using regression-based analysis instead of PCA to account for the effect of using a different assets weighting strategy. RESULTS: Household socio-economic position (SEP) was significantly associated with prevalent TB, regardless of the index used; however, the magnitude of inequalities did vary across indices. A strong association was found for Index 2, suggesting that the exclusion of food-related variables did not reduce the extent of association between SEP and prevalent TB. The weakest association was found for Index 1, indicating that the exclusion of urban assets did not lead to higher extent of TB inequalities. CONCLUSION: TB socio-economic inequalities seem to be robust to the choice of SEP indicator. The epidemiological meaning of the different extent of TB inequalities is unclear. Further studies are needed to confirm our conclusions
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Chromatin accessibility underlies synthetic lethality of SWI/SNF subunits in ARID1A-mutant cancers.
ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, is frequently mutated in cancer. Deficiency in its homolog ARID1B is synthetically lethal with ARID1A mutation. However, the functional relationship between these homologs has not been explored. Here, we use ATAC-seq, genome-wide histone modification mapping, and expression analysis to examine colorectal cancer cells lacking one or both ARID proteins. We find that ARID1A has a dominant role in maintaining chromatin accessibility at enhancers, while the contribution of ARID1B is evident only in the context of ARID1A mutation. Changes in accessibility are predictive of changes in expression and correlate with loss of H3K4me and H3K27ac marks, nucleosome spacing, and transcription factor binding, particularly at growth pathway genes including MET. We find that ARID1B knockdown in ARID1A mutant ovarian cancer cells causes similar loss of enhancer architecture, suggesting that this is a conserved function underlying the synthetic lethality between ARID1A and ARID1B
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