288 research outputs found
Study of Foaming Properties and Effect of the Isomeric Distribution of Some Anionic Surfactants
Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized method very similar to the Ross–Miles foaming tests to identify which surfactants are suitable for applications requiring high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the critical micellar concentrations and at 25 C for both the samples
The consistency condition for the three-point function in dissipative single-clock inflation
We generalize the consistency condition for the three-point function in
single field inflation to the case of dissipative, multi-field, single-clock
models. We use the recently introduced extension of the effective field theory
of inflation that accounts for dissipative effects, to provide an explicit
proof to leading (non-trivial) order in the generalized slow roll parameters
and mixing with gravity scales. Our results illustrate the conditions necessary
for the validity of the consistency relation in situations with many degrees of
freedom relevant during inflation, namely that there is a preferred clock.
Departures from this condition in forthcoming experiments would rule out not
only single field but also a large class of multi-field models.Comment: 26+11 page
A non-Gaussian landscape
Primordial perturbations with wavelengths greater than the observable universe shift the effective background fields in our observable patch from their global averages over the inflating space. This leads to a landscape picture where the properties of our observable patch depend on its location and may significantly differ from the expectation values predicted by the underlying fundamental inflationary model. We show that if multiple fields are present during inflation, this may happen even if our horizon exit would be preceded by only a few e-foldings of inflation. Non-Gaussian statistics are especially affected: for example models of local non-Gaussianity predicting |f_NL|>> 10 over the entire inflating volume can have a probability up to a few tens of percent to generate a non-detectable bispectrum in our observable patch |fNL^{obs.}|<10. In this work we establish systematic connections between the observable local properties of primordial perturbations and the global properties of the inflating space which reflect the underlying high energy physics. We study in detail the implications of both a detection and non-detection of primordial non-Gaussianity by Planck, and discover novel ways of characterising the naturalness of different observational configurations
Effects and Detectability of Quasi-Single Field Inflation in the Large-Scale Structure and Cosmic Microwave Background
Quasi-single field inflation predicts a peculiar momentum dependence in the
squeezed limit of the primordial bispectrum which smoothly interpolates between
the local and equilateral models. This dependence is directly related to the
mass of the isocurvatons in the theory which is determined by the
supersymmetry. Therefore, in the event of detection of a non-zero primordial
bispectrum, additional constraints on the parameter controlling the
momentum-dependence in the squeezed limit becomes an important question. We
explore the effects of these non-Gaussian initial conditions on large-scale
structure and the cosmic microwave background, with particular attention to the
galaxy power spectrum at large scales and scale-dependence corrections to
galaxy bias. We determine the simultaneous constraints on the two parameters
describing the QSF bispectrum that we can expect from upcoming large-scale
structure and cosmic microwave background observations. We find that for
relatively large values of the non-Gaussian amplitude parameters, but still
well within current uncertainties, galaxy power spectrum measurements will be
able to distinguish the QSF scenario from the predictions of the local model. A
CMB likelihood analysis, as well as Fisher matrix analysis, shows that there is
also a range of parameter values for which Planck data may be able distinguish
between QSF models and the related local and equilateral shapes. Given the
different observational weightings of the CMB and LSS results, degeneracies can
be significantly reduced in a joint analysis.Comment: 27 pages, 14 figure
Transport equations for the inflationary trispectrum
We use transport techniques to calculate the trispectrum produced in
multiple-field inflationary models with canonical kinetic terms. Our method
allows the time evolution of the local trispectrum parameters, tauNL and gNL,
to be tracked throughout the inflationary phase. We illustrate our approach
using examples. We give a simplified method to calculate the superhorizon part
of the relation between field fluctuations on spatially flat hypersurfaces and
the curvature perturbation on uniform density slices, and obtain its
third-order part for the first time. We clarify how the 'backwards' formalism
of Yokoyama et al. relates to our analysis and other recent work. We supply
explicit formulae which enable each inflationary observable to be computed in
any canonical model of interest, using a suitable first-order ODE solver.Comment: 24 pages, plus references and appendix. v2: matches version published
in JCAP; typo fixed in Eq. (54
Anomalous Dimensions and Non-Gaussianity
We analyze the signatures of inflationary models that are coupled to strongly
interacting field theories, a basic class of multifield models also motivated
by their role in providing dynamically small scales. Near the squeezed limit of
the bispectrum, we find a simple scaling behavior determined by operator
dimensions, which are constrained by the appropriate unitarity bounds.
Specifically, we analyze two simple and calculable classes of examples:
conformal field theories (CFTs), and large-N CFTs deformed by relevant
time-dependent double-trace operators. Together these two classes of examples
exhibit a wide range of scalings and shapes of the bispectrum, including nearly
equilateral, orthogonal and local non-Gaussianity in different regimes. Along
the way, we compare and contrast the shape and amplitude with previous results
on weakly coupled fields coupled to inflation. This signature provides a
precision test for strongly coupled sectors coupled to inflation via irrelevant
operators suppressed by a high mass scale up to 1000 times the inflationary
Hubble scale.Comment: 40 pages, 10 figure
Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis
In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci
Constraining the WMAP9 bispectrum and trispectrum with needlets
We develop a needlet approach to estimate the amplitude of general (including
non-separable) bispectra and trispectra in the cosmic microwave background, and
apply this to the WMAP 9-year data. We obtain estimates for the `orthogonal'
bispectrum mode, yielding results which are consistent with the WMAP 7-year
data. We do not observe the frequency-dependence suggested by the WMAP team's
analysis of the 9-year data. We present 1- constraints on the `local'
trispectrum shape \gnl/10^5= -4.1\pm 2.3, the `' equilateral model
\gnl^{c_1}/10^6= -0.8\pm 2.9, and the constant model \gnl^{\rm{const}}/10^6=
-0.2\pm 1.8, together with a confidence-level upper bound on the
multifield local parameter \taunl<22000. We estimate the bias on these
parameters produced by point sources. The techniques developed in this paper
should prove useful for other datasets such as Planck.Comment: 21 pages - matches published versio
S.11.1 Influence of digital ulcer healing on disability and daily activity limitations in SSc
Objective. We previously showed that DU significantly increased global and hand disability with a significant impact on activities of daily living (ADLs) and work disability. This study aims to evaluate the impact of digital ulcer (DU) healing on disability and daily activity limitations in SSc. Methods. From January 2008 and June 2009, we prospectively evaluated 189 SSc patients for DU history, disability, employment and occupational status during meetings of the French SSc Patient Association (n = 86, 45.5%) or during hospitalization (n = 103, 54.5%)1. Among the 60 patients with at least one active DU at baseline (M0), 40 patients were followed longitudinally over 6 (3) months. These patients were evaluated for DU history, global and hand disability, health-related quality of life (HRQoL), daily activity limitation and employment status. Results. The median (IQR) age was 57.5 (43.5-68) years and the median (IQR) disease duration was 8.3 (3-16.5) years. Twenty-two (55%) patients had diffuse SSc and 34 (85%) were females. At baseline, a mean of 2.9 (2.8) DU per patient was reported. Thirty-three (82.5%) patients had ischaemic DU, 7 (17.5%) patients had >1 DU associated with calcinosis and 13 (32.5%) patients had mechanical DU. Thirteen (32.5%) patients had >4 DU at baseline. Among the 40 patients, 16 (40%) patients showed complete ulcer healing. In these patients with DU, the presence of calcinosis was associated with a lower probability of healing (P = 0.03). Comparison between healed and no-healed DU patients showed an improvement of hand disability provided by an improvement of the Cochin Hand Function score (P = 0.05)) and a trend towards HAQ domain dressing and grooming (P = 0.06) between M0 and M6 (3) visit in healed patients but not in no-healed patients. Concerning HRQoL, there were no difference for Mental and Physical component Scores of SF-36 but significant improvement of Bodily Pain score (P = 0.04) and Physical Role score (P = 0.05) between M0 and M6 (3) visit in patients with healed DU. The absence of healing was associated with significantly decreased work productivity (P = 0.05), whereas the performance in ADL was not significantly decreased (P = 0.15). Patients who were on sick-leave and who received some help for household tasks at the time of active DU were more likely to heal. Conclusion. For the first time, we provide prospective data with evidence that DU healing is associated with an improvement in hand function. Sick leave was associated with better healing of D
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