475 research outputs found
The Uncertainty in Newton's Constant and Precision Predictions of the Primordial Helium Abundance
The current uncertainty in Newton's constant, G_N, is of the order of 0.15%.
For values of the baryon to photon ratio consistent with both cosmic microwave
background observations and the primordial deuterium abundance, this
uncertainty in G_N corresponds to an uncertainty in the primordial 4He mass
fraction, Y_P, of +-1.3 x 10^{-4}. This uncertainty in Y_P is comparable to the
effect from the current uncertainty in the neutron lifetime, which is often
treated as the dominant uncertainty in calculations of Y_P. Recent measurements
of G_N seem to be converging within a smaller range; a reduction in the
estimated error on G_N by a factor of 10 would essentially eliminate it as a
source of uncertainty in the calculation of the primordial 4He abundance.Comment: 3 pages, no figures, fixed typos, to appear in Phys. Rev.
Brittle asthma
Brittle asthma is a clinical phenotype of the disease at the severe end of the spectrum. Type 1 brittle asthma is characterised by a maintained wide PEF variability (> 40% diurnal variation for > 50% of the time over a period of at least 150 days) despite considerable medical therapy including a dose of inhaled steroids of at least 1500 μg of beclomethasone or equivalent. Type 2 brittle asthma is characterised by sudden acute attacks occurring in less than three hours without an obvious trigger on a background of apparent normal airway function or well controlled asthma. Mechanisms behind the development of brittle asthma include smooth muscle contraction and edema of the airways, which are supported by chronic airway inflammation. Allergy reactions, impairment of local immunity, respiratory infections, psycho-social disorders and reduced perception of worsening airway function are the risk factors for brittle asthma. The diagnosis is based on the analysis of specific symptoms, role of triggers, personal or family history, measurement of lung function and PEF monitoring. Pharmacological treatment of type 1 brittle asthma in addition to the high doses of inhaled and/or oral steroids and bronchodilators includes subcutaneous injections of β2 agonist and inhalation of long acting β2 agonist. The treatment of patients with type 2 brittle asthma includes exclusion of allergen exposure, identification of triggers, self management and management of acute attacks
NLRP3 polymorphisms and response to interferon-beta in multiple sclerosis patients
Evidence exists for a potential modulation of inflammasome activity by interferon beta. Here, we investigated the roles of inflammasomes [absent in melanoma 2 (AIM2); NLR family, CARD domain containing 4 (NLRC4); NLR family, pyrin domain containing 1 and 3 (NLRP1 and NLRP3)] and related cytokines (IL1B, IL10, IL18) in the response to interferon beta in patients with relapsing-remitting multiple sclerosis. Ninety-seven patients treated with interferon beta were classified into responders and non-responders according to clinical criteria after 24 months and clinical-radiological criteria after 12 months of treatment. Messenger RNA expression levels of inflammasomes and cytokines were determined by real-time polymerase chain reaction in peripheral blood mononuclear cells collected before treatment with interferon beta. In a subgroup of patients, NLRP3 and IL1B expression was also determined after 3 months (n = 32) and 12 months (n = 20) of interferon beta treatment. A polymorphism located in the NLRP3 gene, rs35829419, was genotyped in 789 multiple sclerosis patients treated with interferon beta. Baseline mRNA expression levels for NLRP3 and IL1B were increased in peripheral blood mononuclear cells from non-responders compared to responders classified according to clinical criteria after 24 months (P = 0.02 and P = 0.001, respectively). No significant differences were observed for other inflammasomes and related cytokines. Differences in NLRP3 and IL1B expression remained significant following a clinical-radiological classification after 12 months (P = 0.007 and P = 0.02, respectively). After treatment with interferon beta, NLRP3 and IL1B expression was increased in responders but unchanged in non-responders. A trend for association was observed between rs35829419 and interferon beta response (pM-H = 0.08). These results point to a role of the NLRP3 inflammasome and its related cytokine IL1B in the response to interferon beta in patients with relapsing-remitting multiple sclerosis
Current constraints on Cosmological Parameters from Microwave Background Anisotropies
We compare the latest observations of Cosmic Microwave Background (CMB)
Anisotropies with the theoretical predictions of the standard scenario of
structure formation. Assuming a primordial power spectrum of adiabatic
perturbations we found that the total energy density is constrained to be
while the energy density in baryon and Cold Dark
Matter (CDM) are and ,
(all at 68% C.L.) respectively. The primordial spectrum is consistent with
scale invariance, () and the age of the universe is
Gyrs. Adding informations from Large Scale Structure and
Supernovae, we found a strong evidence for a cosmological constant
and a value of the Hubble parameter
. Restricting this combined analysis to flat universes, we put
constraints on possible 'extensions' of the standard scenario. A gravity waves
contribution to the quadrupole anisotropy is limited to be (95%
c.l.). A constant equation of state for the dark energy component is bound to
be (95% c.l.). We constrain the effective relativistic degrees
of freedom and the neutrino chemical potential and (massless neutrinos).Comment: The status of cosmological parameters before WMAP. In press on Phys.
Rev. D., Rapid Communication, 6 pages, 5 figure
Study of the process in the energy region below 0.98 GeV
The cross section of the process was measured in
the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the
energy region below 980 MeV. This measurement was based on about
selected events. The obtained cross section was analyzed
together with the SND and DM2 data in the energy region up to 2
GeV. The -meson parameters: MeV,
MeV and nb were obtained. It was found that the experimental data cannot be
described by a sum of only , , and
resonances contributions. This can be interpreted as a
manifestation of decay, suppressed by -parity, with relative
probability .Comment: 41 pages REVTEX and 34 figure
Hadronic contributions to of the leptons and to the effective fine structure constant
The hadronic contributions to the anomalous magnetic moments of the leptons
and to the effective fine structure constant at the Z-mass are reevaluated
using all presently available data.Comment: 36 pages, 11 Postscript figures, available at
ftp://129.129.40.58/pub/preprints/vapogm2.ps.g
Field Measurements of Terrestrial and Martian Dust Devils
Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types
Reevaluation of the Hadronic Contributions to the Muon g-2 and to alpha(MZ)
We reevaluate the hadronic contributions to the muon magnetic anomaly, and to
the running of the electromagnetic coupling constant at the Z-boson mass. We
include new pi+pi- cross-section data from KLOE, all available multi-hadron
data from BABAR, a reestimation of missing low-energy contributions using
results on cross sections and process dynamics from BABAR, a reevaluation of
all experimental contributions using the software package HVPTools, together
with a reanalysis of inter-experiment and inter-channel correlations, and a
reevaluation of the continuum contributions from perturbative QCD at four
loops. These improvements lead to a decrease in the hadronic contributions with
respect to earlier evaluations. For the muon g-2 we find lowest-order hadronic
contributions of (692.3 +- 4.2) 10^-10 and (701.5 +- 4.7) 10^-10 for the e+e-
based and tau-based analyses, respectively, and full Standard Model predictions
that differ by 3.6 sigma and 2.4 sigma from the experimental value. For the
e+e- based five-quark hadronic contribution to alpha(MZ) we find
Delta_alpha_had[5](MZ)=(275.7 +- 1.0) 10^-4. The reduced electromagnetic
coupling strength at MZ leads to an increase by 7 GeV in the most probable
Higgs boson mass obtained by the standard Gfitter fit to electroweak precision
data.Comment: 13 pages, 10 figures, v2 corrected missing KKpi contribution in Delta
alpha_had(MZ) evaluatio
Whole exome resequencing reveals recessive mutations in TRAP1 in individuals with CAKUT and VACTERL association
Congenital abnormalities of the kidney and urinary tract (CAKUT) account for approximately half of children with chronic kidney disease and they are the most frequent cause of end-stage renal disease in children in the US. However, its genetic etiology remains mostly elusive. VACTERL association is a rare disorder that involves congenital abnormalities in multiple organs including the kidney and urinary tract in up to 60% of the cases. By homozygosity mapping and whole exome resequencing combined with high-throughput mutation analysis by array-based multiplex PCR and next-generation sequencing, we identified recessive mutations in the gene TNF receptor-associated protein 1 (TRAP1) in two families with isolated CAKUT and three families with VACTERL association. TRAP1 is a heat shock protein 90-related mitochondrial chaperone possibly involved in antiapoptotic and endoplasmic reticulum-stress signaling. Trap1 is expressed in renal epithelia of developing mouse kidney E13.5 and in the kidney of adult rats, most prominently in proximal tubules and in thick medullary ascending limbs of Henle’s loop. Thus, we identified mutations in TRAP1 as highly likely causing CAKUT or CAKUT in VACTERL association
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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