320 research outputs found
Spatial variations in the spectral index of polarized synchrotron emission in the 9 yr WMAP sky maps
We estimate the spectral index, beta, of polarized synchrotron emission as
observed in the 9 yr WMAP sky maps using two methods, linear regression ("T-T
plot") and maximum likelihood. We partition the sky into 24 disjoint sky
regions, and evaluate the spectral index for all polarization angles between 0
deg and 85 deg in steps of 5. Averaging over polarization angles, we derive a
mean spectral index of beta_all-sky=-2.99+-0.01 in the frequency range of 23-33
GHz. We find that the synchrotron spectral index steepens by 0.14 from low to
high Galactic latitudes, in agreement with previous studies, with mean spectral
indices of beta_plane=-2.98+-0.01 and beta_high-lat=-3.12+-0.04. In addition,
we find a significant longitudinal variation along the Galactic plane with a
steeper spectral index toward the Galactic center and anticenter than toward
the Galactic spiral arms. This can be well modeled by an offset sinusoidal,
beta(l)=-2.85+0.17sin(2l-90). Finally, we study synchrotron emission in the
BICEP2 field, in an attempt to understand whether the claimed detection of
large-scale B-mode polarization could be explained in terms of synchrotron
contamination. Adopting a spectral index of beta=-3.12, typical for high
Galactic latitudes, we find that the most likely bias corresponds to about 2%
of the reported signal (r=0.003). The flattest index allowed by the data in
this region is beta=-2.5, and under the assumption of a straight power-law
frequency spectrum, we find that synchrotron emission can account for at most
20% of the reported BICEP2 signal.Comment: 11 pages, 9 figures, updated to match version published in Ap
Association between pregravid physical activity and family history of stroke and risk of stillbirth: Population-based cohort study
Objectives: To evaluate whether family history of disease and pregravid lifestyle and cardiovascular risk factors are associated with subsequent stillbirth delivery. Design: Prepregnancy cohort study. Setting: Cohort Norway regional health surveys (1994–2003) linked to Medical Birth Registry of Norway for deliveries through 2012. Participants: 13 497 singleton births (> 22 weeks gestation) in 8478 women. Main outcome measure: Risk of stillbirth evaluated by Poisson regression. Results: Mean (SD) length of follow-up was 5.5 (3.5) years. In analyses adjusting for baseline age and length of follow-up, ≥3 hours of baseline past-year vigorous physical activity per week (resulting in shortness of breath/sweating) was associated with increased risk of stillbirth compared with 18.5 and <25 kg/m2). Vigorous activity of ≥3 hours per week (IRR of 4.50; 95% CI 1.72 to 11.79) and a family history of stroke (IRR of 3.81; 95% CI 1.31 to 11.07) were more strongly related to stillbirth risk among women with a normal BMI than that observed for all women combined. Established risk factors also associated with stillbirth risk. Conclusions: The study identified physical activity and family history of stroke as potential new risk factors for stillbirth delivery.publishedVersio
Children’s views on postsurgical pain in recovery units in Norway: A qualitative study
Aims and objectives: To explore children’s postsurgical experiences with pain and pain management in the recovery unit.
Background: Children’s pain is underestimated and undertreated. Untreated pain can cause unnecessary suffering, increased complication risks, and may lead to chronic pain. Research exploring children’s experiences with postoperative pain and pain management is limited.
Design: A qualitative, exploratory study. The study complied with the Consolidated Criteria for Reporting Qualitative Research (COREQ).
Methods: Children (N=20), 8–16 years old, took part in semi-structured interviews about their experiences with pain and postoperative pain management while they were in a recovery unit. Data were collected at two university hospitals in Norway. Content analysis was used to analyse the data.
Results: Three themes emerged from the interviews; “children’s experiences of what felt unpleasant and painful”, “children’s experiences with pain management” and “children’s recommendations for future pain management”. About half of the children reported moderate to
severe pain while in the recovery unit and they did not always tell their nurses when they had pain. They also reported experiencing pain in places other than their surgical wounds and stated that nausea and vomiting felt unpleasant and painful. The children indicated that pain medications and
the use of non-pharmacological methods helped them cope with their pain and provided several recommendations about how to improve pain management.
Conclusion: Paediatric postoperative pain management remains suboptimal. The children in our study provided useful information about their pain experiences, how to improve pain management and explained why they did not tell their nurses when they were in pain.
Relevance to clinical practice: These findings should direct further improvements in paediatric postoperative pain management, such as increased use of pain assessment tools and preparatory information, as well as more appropriate administration of pain medications.
This is the peer reviewed version of the following article: Twycross, A.M., Smeland, A., Torgun, N., Nybro, L., Rustøen, T., Lundberg, S., and Reinertsen, H. (2019). Children’s views on postsurgical pain in recovery units in Norway: A qualitative study. Journal of Clinical Nursing, which has been published in final form at https://onlinelibrary.wiley.com/doi/full/10.1111/jocn.14788. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions
Long-term response of marine benthic fauna to thin-layer capping with powdered activated carbon in the Grenland fjords, Norway
The Grenland fjords in Norway have a long history of contamination by large emissions of dioxins and mercury. As a possible sediment remediation method in situ, thin-layer capping with powdered activated carbon (AC) mixed with clay was applied at two test sites at 30 m and 95 m depth in the Grenland fjords. This study presents long-term effects of the AC treatment on the benthic community structure, i.e. nine years after capping. Capping with AC significantly reduced the number of species, their abundance and biomass at the two test sites, compared to uncapped reference sites. At the more shallow site, the dominant brittle star species Amphiura filiformis disappeared shortly after capping and did not re-establish nine years after capping. At the deeper site, the AC treatment also caused long-lasting negative effects on the benthic community, but some recovery was observed after nine years. Ecological indices used to assess environmental status did not capture the impaired benthic communities caused by the capping. The present study is the first documentation of negative effects of powdered AC on marine benthic communities on a decadal scale. Our results show that the benefits of reduced contaminant bioavailability from capping with AC should be carefully weighed against the cost of long-term detrimental effects on the benthic community. More research is needed to develop a thin-layer capping material that is efficient at sequestering contaminants without being harmful to benthic species.publishedVersio
A numerical study of heat and mass transfer in an adsorption type hydrogen storage tank
Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.In this paper numerical solutions of a mathematical model
that describes the heat transfer, the fluid flow and the
sorption process in a cylindrical adsorption type hydrogen
storage tank are presented. The tank operates at
cryogenic temperatures and the storage approach is intended
for use in automotive applications. The model is
solved using the spectral element method combined with
an overall third order accurate time stepping scheme. Numerical
experiments show that the time to fill the tank
decreases with increasing charging pressure and that low
conductive heat fluxes constrain the filling process.cs201
Constraints on the spectral index of polarized synchrotron emission from WMAP and Faraday-corrected S-PASS data
We constrain the spectral index of polarized synchrotron emission, ,
by correlating the recently released 2.3 GHz S-Band Polarization All Sky Survey
(S-PASS) data with the 23 GHz 9-year Wilkinson Microwave Anisotropy Probe
(WMAP) sky maps. We sub-divide the S-PASS field, which covers the Southern
Ecliptic hemisphere, into regions, and estimate
the spectral index of polarized synchrotron emission within each region using a
simple but robust T-T plot technique. Three different versions of the S-PASS
data are considered, corresponding to either no correction for Faraday
rotation; Faraday correction based on the rotation measure model presented by
the S-PASS team; or Faraday correction based on a rotation measure model
presented by Hutschenreuter and En{\ss}lin. We find that the correlation
between S-PASS and WMAP is strongest when applying the S-PASS model. Adopting
this correction model, we find that the mean spectral index of polarized
synchrotron emission gradually steepens from at low
Galactic latitudes to at high Galactic latitudes, in good
agreement with previously published results. Finally, we consider two special
cases defined by the BICEP2 and SPIDER fields, and obtain mean estimates of
and , respectively.
Adopting the WMAP 23 GHz sky map bandpass filtered to including angular scales
only between and as a spatial template, we constrain
the root-mean-square synchrotron polarization amplitude to be less than
() at 90 GHz (150 GHz) for the BICEP2 field,
corresponding roughly to a tensor-to-scalar ratio of
(), respectively. Very similar constraints are obtained for the
SPIDER field.Comment: 14 pages, 13 Figures, to be submitted to A&
The QUIET Instrument
The Q/U Imaging ExperimenT (QUIET) is designed to measure polarization in the
Cosmic Microwave Background, targeting the imprint of inflationary
gravitational waves at large angular scales (~ 1 degree). Between 2008 October
and 2010 December, two independent receiver arrays were deployed sequentially
on a 1.4 m side-fed Dragonian telescope. The polarimeters which form the focal
planes use a highly compact design based on High Electron Mobility Transistors
(HEMTs) that provides simultaneous measurements of the Stokes parameters Q, U,
and I in a single module. The 17-element Q-band polarimeter array, with a
central frequency of 43.1 GHz, has the best sensitivity (69 uK sqrt(s)) and the
lowest instrumental systematic errors ever achieved in this band, contributing
to the tensor-to-scalar ratio at r < 0.1. The 84-element W-band polarimeter
array has a sensitivity of 87 uK sqrt(s) at a central frequency of 94.5 GHz. It
has the lowest systematic errors to date, contributing at r < 0.01. The two
arrays together cover multipoles in the range l= 25-975. These are the largest
HEMT-based arrays deployed to date. This article describes the design,
calibration, performance of, and sources of systematic error for the
instrument
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