435 research outputs found
Microwave background constraints on inflationary parameters
We use a compilation of cosmic microwave anisotropy data (including the
recent VSA, CBI and Archeops results), supplemented with an additional
constraint on the expansion rate, to directly constrain the parameters of
slow-roll inflation models. We find good agreement with other papers concerning
the cosmological parameters, and display constraints on the power spectrum
amplitude from inflation and the first two slow-roll parameters, finding in
particular that . The technique we use for parametrizing
inflationary spectra may become essential once the data quality improves
significantly.Comment: 6 pages LaTeX file with figures incorporated. Major revisions
including incorporation of new datasets (CBI and Archeops). Slow-roll
inflation module for use with the CAMB program can be found at
http://astronomy.cpes.susx.ac.uk/~sleach/inflation
From the production of primordial perturbations to the end of inflation
In addition to generating the appropriate perturbation power spectrum, an
inflationary scenario must take into account the need for inflation to end
subsequently. In the context of single-field inflation models where inflation
ends by breaking of the slow-roll condition, we constrain the first and second
derivatives of the inflaton potential using this additional requirement. We
compare this with current observational constraints from the primordial
spectrum and discuss several issues relating to our results.Comment: RevTex4, 6 pages, 7 figures. To match version accepted by PR
The WMAP normalization of inflationary cosmologies
We use the three-year WMAP observations to determine the normalization of the
matter power spectrum in inflationary cosmologies. In this context, the
quantity of interest is not the normalization marginalized over all parameters,
but rather the normalization as a function of the inflationary parameters n and
r with marginalization over the remaining cosmological parameters. We compute
this normalization and provide an accurate fitting function. The statistical
uncertainty in the normalization is 3 percent, roughly half that achieved by
COBE. We use the k-l relation for the standard cosmological model to identify
the pivot scale for the WMAP normalization. We also quote the inflationary
energy scale corresponding to the WMAP normalization.Comment: 4 pages RevTex4 with two figure
Influence of HLA Class II Polymorphism on Predicted Cellular Immunity Against SARS-CoV-2 at the Population and Individual Level.
Development of adaptive immunity after COVID-19 and after vaccination against SARS-CoV-2 is predicated on recognition of viral peptides, presented on HLA class II molecules, by CD4+ T-cells. We capitalised on extensive high-resolution HLA data on twenty five human race/ethnic populations to investigate the role of HLA polymorphism on SARS-CoV-2 immunogenicity at the population and individual level. Within populations, we identify wide inter-individual variability in predicted peptide presentation from structural, non-structural and accessory SARS-CoV-2 proteins, according to individual HLA genotype. However, we find similar potential for anti-SARS-CoV-2 cellular immunity at the population level suggesting that HLA polymorphism is unlikely to account for observed disparities in clinical outcomes after COVID-19 among different race/ethnic groups. Our findings provide important insight on the potential role of HLA polymorphism on development of protective immunity after SARS-CoV-2 infection and after vaccination and a firm basis for further experimental studies in this field
An overview of systematic reviews of complementary and alternative therapies for fibromyalgia using both AMSTAR and ROBIS as quality assessment tools
Abstract Background Fibromyalgia (FM) is a chronic, debilitating pain disorder. Dissatisfaction with conventional medicine can lead people with FM to turn to complementary and alternative medicine (CAM). Two previous overviews of systematic reviews of CAM for FM have been published, but they did not assessed for risk of bias in the review process. Methods Five databases Medline, Embase, AMED (via OVID), Web of Science and Central were searched from their inception to December 2015. Reference lists were hand-searched. We had two aims: the first was to provide an up-to-date and rigorously conducted synthesis of systematic reviews of CAM literature on FM; the second was to evaluate the quality of the available systematic review evidence using two different tools: AMSTAR (Shea et al. BMC Med Res Methodol 15; 7:10, 2007) and a more recently developed tool ROBIS (Whiting et al. J Clin Epidemiol 69:225-34, 2016) specifically designed to assess risk of bias in systematic reviews. Any review that assessed one of eight CAM therapies for participants diagnosed with FM was considered. The individual studies had to be randomised controlled trials where the intervention was compared to placebo, treatment as usual or waitlist controls to be included. The primary outcome measure was pain, and the secondary outcome measure was adverse events. Results We identified 15 reviews that met inclusion criteria. There was low-quality evidence that acupuncture improves pain compared to no treatment or standard treatment, but good evidence that it is no better than sham acupuncture. The evidence for homoeopathy, spinal manipulation and herbal medicine was limited. Conclusions Overall, five reviews scored 6 or above using the AMSTAR scale and the inter-rater agreement was good (83.6%), whereas seven reviews achieved a low risk of bias rating using ROBIS and the inter-rater agreement was fair (60.0%). No firm conclusions were drawn for efficacy of either spinal manipulation or homoeopathy for FM. There is limited evidence for topical Capsicum, but further research is required. There is some evidence to support the effectiveness of acupuncture for FM, but further high-quality trials are needed to investigate its benefits, harms and mechanisms of action, compared with no or standard treatment. Systematic review registration PROSPERO CRD42016035846
Constraining slow-roll inflation with WMAP and 2dF
We constrain slow-roll inflationary models using the recent WMAP data
combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the
slow-roll parameters to be and . For inflation models
we find that at the 2 and levels,
indicating that the model is under very strong pressure from
observations. We define a convergence criterion to judge the necessity of
introducing further power spectrum parameters such as the spectral index and
running of the spectral index. This criterion is typically violated by models
with large negative running that fit the data, indicating that the running
cannot be reliably measured with present data.Comment: 8 pages RevTeX4 file with six figures incorporate
How long before the end of inflation were observable perturbations produced?
We reconsider the issue of the number of e-foldings before the end of
inflation at which observable perturbations were generated. We determine a
plausible upper limit on that number for the standard cosmology which is around
60, with the expectation that the actual value will be up to 10 below this. We
also note a special property of the model which reduces the
uncertainties in that case and favours a higher value, giving a fairly definite
prediction of 64 e-foldings for that model. We note an extreme (and highly
implausible) situation where the number of e-foldings can be even higher,
possibly up to 100, and discuss the shortcomings of quantifying inflation by
e-foldings rather than by the change in . Finally, we discuss the impact of
non-standard evolution between the end of inflation and the present, showing
that again the expected number of e-foldings can be modified, and in some cases
significantly increased.Comment: 7 pages RevTeX4 file with one figure incorporated. Minor updates to
match version accepted by Physical Review
The Coastline Evolution Model 2D (CEM2D) V1.1
Coasts are among the most intensely used environments on the planet, but they also present dynamic and unique hazards, including flooding and erosion. Sea level rise and changing wave climates will alter patterns of erosion and deposition, but some existing coastline evolution models are unable to simulate these effects due to their one-dimensional representation of the systems or the sediment transport processes. In this paper, the development and application of the Coastline Evolution Model 2D (CEM2D) are presented, a model which incorporates these influences. The model has been developed from the established CEM and is capable of simulating fundamental cause–effect relationships in coastal systems. The two-dimensional storage and transport of sediment in CEM2D, which are only done in one-dimension in CEM, mean it is also capable of exploring the influence of a variable water level on sediment transport and the formation and evolution of morphological features and landforms at the mesoscale. The model sits between one-dimensional and three-dimensional models, with the advantage of increased complexity and detail in model outputs compared to the former but with more efficiency and less computational expense than the latter
What predicts regression from pre-diabetes to normal glucose regulation following a primary care nurse-delivered dietary intervention? A study protocol for a prospective cohort study
Introduction Pre-diabetes is a high-risk state for the development of type 2 diabetes mellitus (T2DM) and cardiovascular disease. Regression to normoglycaemia, even if transient, significantly reduces the risk of developing T2DM. The primary aim of this mixed-methods study is to determine if there are clinically relevant differences among those with pre-diabetes and excess weight who regress to normoglycaemia, those who have persistent pre-diabetes and those who progress to T2DM following participation in a 6-month primary care nurse-delivered pre-diabetes dietary intervention. Incidence of T2DM at 2 years will be examined. Methods and analysis Four hundred participants with pre-diabetes (New Zealand definition glycated haemoglobin 41–49 mmol/mol) and a body mass index \u3e25 kg/m2 will be recruited through eight primary care practices in Hawke’s Bay, New Zealand. Trained primary care nurses will deliver a 6-month structured dietary intervention, followed by quarterly reviews for 18 months post-intervention. Clinical data, data on lifestyle factors and health-related quality of life (HR-QoL) and blood samples will be collected at baseline, 6 months, 12 months and 24 months. Sixty participants purposefully selected will complete a semi-structured interview following the 6-month intervention. Poisson regression with robust standard errors and clustered by practice will be used to identify predictors of regression or progression at 6 months, and risk factors for developing T2DM at 2 years. Qualitative data will be analysed thematically. Changes in HR-QoL will be described and potential cost savings will be estimated from a funder’s perspective at 2 years. Ethics and dissemination This study was approved by the Northern A Health and Disability Ethics Committee, New Zealand (Ethics Reference: 17/NTA/24). Study results will be presented to participants, published in peer-reviewed journals and presented at relevant conferences. Trial registration number ACTRN12617000591358; Pre-results
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