4,471 research outputs found
Recommended from our members
Airborne measurement of inorganic ionic components of fine aerosol particles using the particle-into-liquid sampler coupled to ion chromatography technique during ACE-Asia and TRACE-P
Intercomparisons of airborne measurements of aerosol ionic chemical composition during TRACE-P and ACE-Asia
As part of the two field studies, Transport and Chemical Evolution over the Pacific (TRACE-P) and the Asian Aerosol Characterization Experiment (ACE-Asia), the inorganic chemical composition of tropospheric aerosols was measured over the western Pacific from three separate aircraft using various methods. Comparisons are made between the rapid online techniques of the particle into liquid sampler (PILS) for measurement of a suite of fine particle a mist chamber/ion chromatograph (MC/IC) measurement of fine sulfate, and the longer time-integrated filter and micro-orifice impactor (MOI) measurements. Comparisons between identical PILS on two separate aircraft flying in formation showed that they were highly correlated (e.g., sulfate r2 of 0.95), but were systematically different by 10 Âą 5% (linear regression slope and 95% confidence bounds), and had generally higher concentrations on the aircraft with a low-turbulence inlet and shorter inlet-to-instrument transmission tubing. Comparisons of PILS and mist chamber measurements of fine sulfate on two different aircraft during formation flying had an r 2 of 0.78 and a relative difference of 39% Âą 5%. MOI ionic data integrated to the PILS upper measurement size of 1.3 mm sampling from separate inlets on the same aircraft showed that for sulfate, PILS and MOI were within 14% Âą 6% and correlated with an r 2 of 0.87. Most ionic compounds were within Âą30%, which is in the range of differences reported between PILS and integrated samplers from ground-based comparisons. In many cases, direct intercomparison between the various instruments is difficult due to differences in upper-size detection limits. However, for this study, the results suggest that the fine particle mass composition measured from aircraft agree to within 30â40%
Recommended from our members
Characteristics and influence of biosmoke on the fine-particle ionic composition measured in Asian outflow during the Transport and Chemical Evolution Over the Pacific (TRACE-P) experiment
Commissioning of the CMS High Level Trigger
The CMS experiment will collect data from the proton-proton collisions
delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to
14 TeV. The CMS trigger system is designed to cope with unprecedented
luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger
architecture only employs two trigger levels. The Level-1 trigger is
implemented using custom electronics, while the High Level Trigger (HLT) is
based on software algorithms running on a large cluster of commercial
processors, the Event Filter Farm. We present the major functionalities of the
CMS High Level Trigger system as of the starting of LHC beams operations in
September 2008. The validation of the HLT system in the online environment with
Monte Carlo simulated data and its commissioning during cosmic rays data taking
campaigns are discussed in detail. We conclude with the description of the HLT
operations with the first circulating LHC beams before the incident occurred
the 19th September 2008
Results from the first use of low radioactivity argon in a dark matter search
Liquid argon is a bright scintillator with potent particle identification
properties, making it an attractive target for direct-detection dark matter
searches. The DarkSide-50 dark matter search here reports the first WIMP search
results obtained using a target of low-radioactivity argon. DarkSide-50 is a
dark matter detector, using two-phase liquid argon time projection chamber,
located at the Laboratori Nazionali del Gran Sasso. The underground argon is
shown to contain Ar-39 at a level reduced by a factor (1.4 +- 0.2) x 10^3
relative to atmospheric argon. We report a background-free null result from
(2616 +- 43) kg d of data, accumulated over 70.9 live-days. When combined with
our previous search using an atmospheric argon, the 90 % C.L. upper limit on
the WIMP-nucleon spin-independent cross section based on zero events found in
the WIMP search regions, is 2.0 x 10^-44 cm^2 (8.6 x 10^-44 cm^2, 8.0 x 10^-43
cm^2) for a WIMP mass of 100 GeV/c^2 (1 TeV/c^2 , 10 TeV/c^2).Comment: Accepted by Phys. Rev.
Ultrasound-Guided Radiofrequency Thermal Ablation of Uterine Fibroids: Medium-Term Follow-Up
Previous studies have shown that radiofrequency thermal ablation (RFA) of uterine fibroids through a percutaneous ultrasound (US)-guided procedure is an effective and safe minimally invasive treatment, with encouraging short-term results. The aim of this study was to assess the results in terms of volume reduction and clinical symptoms improvement in the midterm follow-up of fibroids with a diameter of up to 8Â cm. Eleven premenopausal females affected by symptomatic fibroids underwent percutaneous US-guided RFA. Symptom severity and reduction in volume were evaluated at 1, 3, 6, 9, and 12Â months. The mean symptom score (SSS) before the procedure was 50.30 (range 31.8â67.30), and the average quality of life (QOL) score value was 62 (range 37.20â86.00). The mean basal diameter was 5.5Â cm (range 4.4â8) and the mean volume was 101.5Â cm3 (range 44.58â278Â cm3). The mean follow-up was 9Â months (range 3â12Â months). The mean SSS value at the end of the follow-up was 13.38 (range 0â67.1) and the QOL 90.4 (range 43.8â100). At follow-up the mean diameter was 3.0Â cm (range 1.20â4.5Â cm), and the mean volume was 18Â cm3 (range 0.90â47.6Â cm3). In 10 of 11 patients we obtained total or partial regression of symptoms. In one case the clinical manifestations persisted and it was thus considered unsuccessful. In conclusion, US-guided percutaneous RFA is a safe and effective treatment even for fibroids up to 8Â cm
The Effect of Interleukin-4 and Amphiregulin on the Proliferation of Human Airway Smooth Muscle Cells and Cytokine Release
Airway smooth muscle (ASM) hyperplasia and angiogenesis are important features associated with airway remodeling. We investigated the effect of IL-4 and amphiregulin, an epidermal growth factor family member, on the proliferation of human ASM cells and on the release of vascular endothelial growth factor (VEGF) and monocyte chemotactic protein (MCP)-1 from human ASM cells. Human ASM cells were growth-arrested for 48 hr and incubated with platelet-derived growth factor (PDGF)-BB, interleukin (IL)-4, amphiregulin, and VEGF to evaluate cell proliferation. The cells were treated with PDGF, IL-4 and amphiregulin to evaluate the release of VEGF, MCP-1. IL-4 suppressed unstimulated and PDGF-stimulated ASM cell proliferation. Amphiregulin stimulated ASM cell proliferation in a dose-dependent manner. VEGF did not have any influence on ASM cell proliferation. IL-4 stimulated VEGF secretion by the ASM cells in a dose-dependent manner and showed added stimulatory effects when co-incubated with PDGF. Amphiregulin did not promote VEGF secretion. IL-4 and amphiregulin showed no stimulatory effects on MCP-1 secretion. The results of this study showed that IL-4 had bifunctional effects on airway remodeling, one was the suppression of the proliferation of the ASM cells and the other was the promotion of VEGF release by the ASM cells, and amphiregulin can promote human ASM cell proliferation
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
- âŚ