584 research outputs found
Initial investigation of the wavelength dependence of optical properties measured with a new multi-pass Aerosol Extinction Differential Optical Absorption Spectrometer (AE-DOAS)
Atmospheric aerosols directly affect climate by scattering and absorbing radiation. The magnitude of the impact is dependent upon the wavelength of light, but is often estimated near 550 nm. When light scattering and absorption by aerosols is approximated, the wavelength dependence of the refractive index for speciïŹc components is lost. As a result, climate models would have inherent uncertainties for aerosol contributions to radiative forcing when considering the entire solar spectrum. An aerosol extinction differential optical absorption spectrometer has been developed to directly measure aerosol extinction at mid-ultraviolet to near infrared wavelengths. The instrument consists of a spectrometer coupled to a closed White-type multi-pass gas cell with an adjustable path length of up to approximately 20 m. Laboratory measurements of various gases are compared with known absorption cross sections. Additionally, the extinction of monodisperse samples of polystyrene latex spheres are measured and compared to Mie theory generated with refractive index values from the literature to validate the new instrument. The polystyrene experiments also emphasize the ability of the new instrument to retrieve the wavelength dependent refractive index, especially in the ultraviolet wavelength regions where variability is expected. The spectrometer will be a signiïŹcant advancement for determining wavelength dependent complex refractive indices in future laboratory studies as well as provide the ability to monitor ambient aerosol light extinction
The activity of employer unions in perspective
As two of the employer representatives thanked by the authors of the article The inactivitesof employer unions by P Brosnan. P Walsh and P Rowe for their advice. we are prevented by modesty (and other sentiment) from bearing the burden of any credit for its contents and interpretations
Spectral aerosol extinction (SpEx): a new instrument for in situ ambient aerosol extinction measurements across the UV/visible wavelength range
We introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300â 700 nm wavelength range, the spectral aerosol extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres (PSLs) agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at 450, 530, and 630 nm using CAPS PMex instruments in a series of 22 tests including nonabsorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx measurements are expected to help identify the presence of ambient brown carbon due to its 300 nm lower wavelength limit compared to measurements limited to longer UV and visible wavelengths. Extinction spectra obtained with SpEx contain more information than can be conveyed by a simple power law fit (typically represented by Ă
ngström exponents). Planned future improvements aim to lower detection limits and ruggedize the instrument for mobile operation
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Women reporting sport: Still a manâs game?
While it is generally known that sports journalism is an area of gender disparity, no major academic study has established the proportion of women sports writers in the UK press. Although female sports broadcasters have increased their visibility in the United Kingdom, the same is not true in the print media. This research first examines the current visibility of women sports journalists in the national UK press, by counting by-lines according to gender. Second, a study explores if the 2012 London Olympic Games had any effect on the proportion of female sports writers in the UK press, by comparing sports by-lines in a sample 6 months before and after the games. Furthermore, these results are compared to a decade earlier to see if the situation has improved. The findings indicate that the proportion of female sports writers in the UK press is lower than in comparable countries, with little improvement over time
What Does Severe Acute Respiratory Syndrome Coronavirus 2 Mean for Global Pneumonia Prevention, Diagnosis, and Treatment?
An extreme proto-cluster of luminous dusty starbursts in the early Universe
We report the identification of an extreme proto-cluster of galaxies in the
early Universe whose core (nicknamed Distant Red Core, DRC) is formed by at
least ten dusty star-forming galaxies (DSFGs), confirmed to lie at via detection of [CI](1-0), CO(6-5), CO(4-3),
CO(2-1) and emission lines, detected
using ALMA and ATCA. The spectroscopically-confirmed components of the
proto-cluster are distributed over a region
and have a collective obscured star-formation rate (SFR) of , considerably higher than has been seen before in any
proto-cluster of galaxies or over-densities of DSFGs at . Most of
the star formation is taking place in luminous DSFGs since no Ly
emitters are detected in the proto-cluster core, apart from a Ly blob
located next to one of the DRC dusty components and extending over . The total obscured SFR of the proto-cluster could rise to if all the members of an over-density
of bright DSFGs discovered around DRC in a wide-field LABOCA 870-m image
are part of the same structure. The total halo mass of DRC could be as high as
and could be the progenitor of a Coma-like
cluster at . The relatively short gas-depletion times of the DRC
components suggest either the presence of a mechanism able to trigger extreme
star formation simultaneously in galaxies spread over a few hundred kpc or the
presence of gas flows from the cosmic web able to sustain star formation over
several hundred million years.Comment: Submitted to ApJ. Minor updates added, including a change of the
source name. Comments welcom
Striving for excellence in maternity care: The Maternity Stream of the City of Sanctuary.
yesAsylum-seeking and refugee (AS&R) women living in the UK often have complex health and social care needs, with poor underlying mental and physical health and an increased risk of negative pregnancy outcomes. Despite this, AS&R women are less likely to attend for timely maternity care and when they do, care may be poor, with staff not understanding their specific needs and displaying poor attitudes. This article discusses the Maternity Stream of the City of Sanctuary and how this charity aims to work with statutory and voluntary sector maternity-related services and groups to develop services that are inclusive for AS&R women and meet their specific needs. Volunteer AS&R women are central to the activities of the Maternity Stream and this article discusses how they engage with midwives and other maternity workers to facilitate the development of services that may ultimately improve pregnancy outcomes for AS&R women
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