153 research outputs found
Investigating the Cosmic-Ray Ionization Rate Near the Supernova Remnant IC 443 Through H3+ Observations
Observational and theoretical evidence suggests that high-energy Galactic
cosmic rays are primarily accelerated by supernova remnants. If also true for
low-energy cosmic rays, the ionization rate near a supernova remnant should be
higher than in the general Galactic interstellar medium (ISM). We have searched
for H3+ absorption features in 6 sight lines which pass through molecular
material near IC 443---a well-studied case of a supernova remnant interacting
with its surrounding molecular material---for the purpose of inferring the
cosmic-ray ionization rate in the region. In 2 of the sight lines (toward ALS
8828 and HD 254577) we find large H3+ column densities, N(H3+)~3*10^14 cm^-2,
and deduce ionization rates of zeta_2~2*10^-15 s^-1, about 5 times larger than
inferred toward average diffuse molecular cloud sight lines. However, the 3
sigma upper limits found for the other 4 sight lines are consistent with
typical Galactic values. This wide range of ionization rates is likely the
result of particle acceleration and propagation effects, which predict that the
cosmic-ray spectrum and thus ionization rate should vary in and around the
remnant. While we cannot determine if the H3+ absorption arises in post-shock
(interior) or pre-shock (exterior) gas, the large inferred ionization rates
suggest that IC 443 is in fact accelerating a large population of low-energy
cosmic rays. Still, it is unclear whether this population can propagate far
enough into the ISM to account for the ionization rate inferred in diffuse
Galactic sight lines.Comment: 14 pages, 3 figures, 4 table
Quality approaches to allow multi-site equivalence in pluripotent stem cell based product manufacturing [Abstract]
Quality approaches to allow multi-site equivalence in pluripotent stem cell based product manufacturing [Abstract
Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
Observations of H3+ in the Galactic diffuse interstellar medium (ISM) have
led to various surprising results, including the conclusion that the cosmic-ray
ionization rate (zeta_2) is about 1 order of magnitude larger than previously
thought. The present survey expands the sample of diffuse cloud sight lines
with H3+ observations to 50, with detections in 21 of those. Ionization rates
inferred from these observations are in the range (1.7+-1.3)x10^-16
s^-1<zeta_2<(10.6+-8.2)x10^-16 s^-1 with a mean value of
zeta_2=(3.5^+5.3_-3.0)x10^-16 s^-1. Upper limits (3 sigma) derived from
non-detections of H3+ are as low as zeta_2<0.4x10^-16 s^-1. These low
upper-limits, in combination with the wide range of inferred cosmic-ray
ionization rates, indicate variations in zeta_2 between different diffuse cloud
sight lines. A study of zeta_2 versus N_H (total hydrogen column density) shows
that the two parameters are not correlated for diffuse molecular cloud sight
lines, but that the ionization rate decreases when N_H increases to values
typical of dense molecular clouds. Both the difference in ionization rates
between diffuse and dense clouds and the variation of zeta_2 among diffuse
cloud sight lines are likely the result of particle propagation effects. The
lower ionization rate in dense clouds is due to the inability of low-energy
(few MeV) protons to penetrate such regions, while the ionization rate in
diffuse clouds is controlled by the proximity of the observed cloud to a site
of particle acceleration.Comment: 48 pages, 19 figures, 4 tables, accepted for publication in Ap
Cosmology with the Highly Redshifted 21cm Line
In addition to being a probe of Cosmic Dawn and Epoch of Reionization
astrophysics, the 21cm line at is also a powerful way to constrain
cosmology. Its power derives from several unique capabilities. First, the 21cm
line is sensitive to energy injections into the intergalactic medium at high
redshifts. It also increases the number of measurable modes compared to
existing cosmological probes by orders of magnitude. Many of these modes are on
smaller scales than are accessible via the CMB, and moreover have the advantage
of being firmly in the linear regime (making them easy to model theoretically).
Finally, the 21cm line provides access to redshifts prior to the formation of
luminous objects. Together, these features of 21cm cosmology at provide
multiple pathways toward precise cosmological constraints. These include the
"marginalizing out" of astrophysical effects, the utilization of redshift space
distortions, the breaking of CMB degeneracies, the identification of signatures
of relative velocities between baryons and dark matter, and the discovery of
unexpected signs of physics beyond the CDM paradigm at high redshifts.Comment: Science white paper submitted to Decadal 2020 surve
Patient prioritisation of items to develop the Patient‐Reported Impact of Dermatological Diseases measure: A global Delphi study
Background: The Global Research on the Impact of Dermatological Diseases (GRIDD) project is developing the new Patient‐Reported Impact of Dermatological Diseases (PRIDD) measure. PRIDD measures the impact of dermatological conditions on the patient's life. Objectives: This study aimed to seek consensus from patients on which items to prioritize for inclusion in PRIDD. Methods: A modified, two‐round Delphi study was conducted. Adults (≥18 years) with dermatological conditions were recruited. The survey consisted of a demographic's questionnaire and 263 potential impact items in six languages. Quantitative data used Likert‐type ranking scales and analysed against consensus criteria. Qualitative data collected free text responses for additional feedback and a framework analysis was conducted. Results: 1154 people representing 90 dermatological conditions from 66 countries participated. Items were either removed (n = 79), edited (n = 179) or added (n = 2), based on consensus thresholds and qualitative feedback. Results generated the first draft of PRIDD with 27 items across five impact domains. Conclusion: This Delphi study resulted in the draft version of PRIDD, ready for psychometric testing. The triangulated data helped refine the existing conceptual framework of impact. PRIDD has since been pilot tested with patients and is currently undergoing psychometric testing
Training for managing impacted fetal head at caesarean birth: multimethod evaluation of a pilot
Background Implementation of national multiprofessional training for managing the obstetric emergency of impacted fetal head (IFH) at caesarean birth has potential to improve quality and safety in maternity care, but is currently lacking in the UK.
Objectives To evaluate a training package for managing IFH at caesarean birth with multiprofessional maternity teams.
Methods The training included an evidence-based lecture supported by an animated video showing management of IFH, followed by hands-on workshops and real-time simulations with use of a birth simulation trainer, augmented reality and management algorithms. Guided by the Kirkpatrick framework, we conducted a multimethod evaluation of the training with multiprofessional maternity teams. Participants rated post-training statements about relevance and helpfulness of the training and pre-training and post-training confidence in their knowledge and skills relating to IFH (7-point Likert scales, strongly disagree to strongly agree). An ethnographer recorded sociotechnical observations during the training. Participants provided feedback in post-training focus groups.
Results Participants (N=57) included 21 midwives, 25 obstetricians, 7 anaesthetists and 4 other professionals from five maternity units. Over 95% of participants agreed that the training was relevant and helpful for their clinical practice and improving outcomes following IFH. Confidence in technical and non-technical skills relating to managing IFH was variable before the training (5%–92% agreement with the pre-training statements), but improved in nearly all participants after the training (71%–100% agreement with the post-training statements). Participants and ethnographers reported that the training helped to: (i) better understand the complexity of IFH, (ii) recognise the need for multiprofessional training and management and (iii) optimise communication with those in labour and their birth partners.
Conclusions The evaluated training package can improve self-reported knowledge, skills and confidence of multiprofessional teams involved in management of IFH at caesarean birth. A larger-scale evaluation is required to validate these findings and establish how best to scale and implement the training
Stabbing News: Articulating Crime Statistics in the Newsroom
There is a comprehensive body of scholarly work regarding the way media represent crime and how it is constructed in the media narrative as a news item. These works have often suggested that in many cases public anxieties in relation to crime levels are not justified by actual data. However, few works have examined the gathering and dissemination of crime statistics by non-specialist journalists and the way crime statistics are gathered and used in the newsroom. This article seeks to explore in a comparative manner how journalists in newsrooms access and interpret quantitative data when producing stories related to crime. In so doing, the article highlights the problems and limitations of journalists in dealing with crime statistics as a news source, while assessing statistics-related methodologies and skills used in the newsrooms across the United Kingdom when producing stories related to urban crime
Volatile organic compound mixing ratios above Beijing in November and December 2016
Volatile organic compounds (VOCs) are emitted into the atmosphere from vegetation and anthropogenic
sources such as fossil fuel combustion, biomass burning and the evaporation of petroleum products. These
compounds play an important role in the chemistry of the lower atmosphere through secondary organic aerosol
(SOA) formation and facilitating the formation of tropospheric ozone. As well as their indirect impact on human
health via the formation of ozone and SOA, some VOCs, including benzene, directly affect human health adversely.
Here we report VOC mixing ratios measured in Beijing during a 5 week intensive field campaign from the
7th November to the 10th December 2016. This work was carried out as part of the Sources and Emissions
of Air Pollutants in Beijing (AIRPOLL-Beijing) work project within the Air Pollution and Human Health in
a Developing Megacity (APHH-Beijing) research programme. APHH is a large multi-institutional study which
aims to record the concentrations and identify the sources of urban air pollutants in Beijing, determine exposure,
understand their effects on human health, and to identify solutions.
VOC mixing ratios were recorded using a Proton Transfer Reaction-Time of Flight-Mass Spectrometer
(PTR-ToF-MS, Ionicon Analytik) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS, SYFT Technologies).
During the measurement period Beijing was subject to multiple pollution events that alternated with periods
of relatively good air quality, allowing the VOCs within the polluted air masses to be identified and quantified.
VOCs were sampled at 102 m with additional gradient measurements made at 3, 15, 32 and 64 m providing a
vertical profile of VOC mixing ratios. Mixing ratios of methanol, acetonitrile, acetaldehyde, acetone, isoprene and
aromatics species will be reported together with a discussion of potential sources. Comparisons will then be drawn
with other large cities
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