Neutral kaon pairs produced in ϕ decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating ...process ϕ→KSKL→π+π−π+π− based on 1.7 fb−1 of data collected by the KLOE experiment at the Frascati ϕ-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters Δaμ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:Δa0=(−6.0±7.7stat±3.1syst)×10−18 GeV,ΔaX=(0.9±1.5stat±0.6syst)×10−18 GeV,ΔaY=(−2.0±1.5stat±0.5syst)×10−18 GeV,ΔaZ=(3.1±1.7stat±0.5syst)×10−18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension.
We present a new limit on the production of a light dark-force mediator with the KLOE detector at DAΦNE. This boson, called U, has been searched for in the decay ϕ→ηU, U→e+e−, analyzing the decay ...η→π0π0π0 in a data sample of 1.7 fb−1. No structures are observed in the e+e− invariant mass distribution over the background. This search is combined with a previous result obtained from the decay η→π+π−π0, increasing the sensitivity. We set an upper limit at 90% C.L. on the ratio between the U boson coupling constant and the fine structure constant of α′/α<1.7×10−5 for 30<MU<400 MeV and α′/α⩽8×10−6 for the sub-region 50<MU<210 MeV. This result assumes the Vector Meson Dominance expectations for the ϕηγ⁎ transition form factor. The dependence of this limit on the transition form factor has also been studied.
► Correlation of ultra high energy cosmic rays with nearby extragalactic matter. ► Evidence of anisotropy in ultra high energy arrival directions. ► Autocorrelation of arrival directions shows modest ...excess over broad range of small angular scales. ► The largest observed excess occurs in the region around the radiogalaxy Cen A.
Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen–Zatsepin–Kuz’min energy threshold, 6
×
10
19
eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1° from the position of an active galactic nucleus within 75
Mpc (using the Véron-Cetty and Véron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is
38
-
6
+
7
%
, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of
69
-
13
+
11
%
. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.
To evaluate the effectiveness of a nutritional strategy based on two components and adapted for the public health system on blood pressure, cardiometabolic features, self-care, qualify of life and ...diet quality in individuals with hypertension.
NUPRESS was an open-label, parallel-group, superiority randomized controlled clinical trial in which participants at least 21 years with hypertension and poorly controlled blood pressure were randomly assigned (1 : 1 allocation ratio) to either an individualized dietary prescription according to nutritional guidelines (control group, n = 205); or a two-component nutrition strategy, including a goal-directed nutritional counseling and mindfulness techniques (NUPRESS intervention group, n = 205). Primary outcomes were SBP (mmHg) after 24 weeks of follow up and blood pressure control, defined as either having SBP more than 140 mmHg at baseline and achieving 140 mmHg or less after follow-up or having SBP 140 mmHg or less at baseline and reducing the frequency of antihypertensive drugs in use after follow-up.
In total, 410 participants were randomized and submitted to an intention-to-treat analysis regarding primary outcomes. Both groups decreased blood pressure, but after adjusting for baseline values, there was no significant difference between them on SBP intervention-control difference: -0.03 (-3.01; 2.94); P = 0.98 nor blood pressure control odds ratio 1.27 (0.82; 1.97); P = 0.28. No differences between groups were also detected regarding secondary and tertiary outcomes.
There was no difference between a two-component nutritional strategy and an established dietary intervention on blood pressure in participants with hypertension.
Genetic variation is known to affect response to calcium channel blockers (CCBs) among different populations. This study aimed to determine the genetic variations associated with poor response to ...this class of antihypertensive drugs among Filipinos.One hundred eighty one hypertensive participants on CCBs therapy were included in an unmatched case-control study. Genomic deoxyribonucleic acid were extracted and genotyped for selected genetic variants. Regression analysis was used to determine the association of genetic and clinical variables with poor response to medication.The variant rs1458038 near fibroblast growth factor 5 gene showed significant association with poor blood pressure-lowering response based on additive effect (CT genotype: adjusted OR 3.41, P = .001; TT genotype: adjusted OR 6.72, P < .001).These findings suggest that blood pressure response to calcium channels blockers among Filipinos with hypertension is associated with gene variant rs1458038 near fibroblast growth factor 5 gene. Further studies are recommended to validate such relationship of the variant to the CCB response.
The existence of a light dark force mediator has been tested with the KLOE detector at DAΦNE. This particle, called U, is searched for using the decay chain ϕ→ηU, η→π+π−π0, U→e+e−. No evidence is ...found in 1.5 fb−1 of data. The resulting exclusion plot covers the mass range 5<MU<470 MeV, setting an upper limit on the ratio between the U boson coupling constant and the fine structure constant, α′/α, of ⩽2×10−5 at 90% C.L. for 50<MU<420 MeV.
Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The ...satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.
The fluorescence detector of the Pierre Auger Observatory Abreu, P.; Aguirre, C.; Argirò, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2010, Letnik:
620, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector ...to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.
A simple sol–gel based electrospinning method has been applied for the synthesis of vanadium oxide/polyvinyl acetate (V2O5/PVAC) fibers for gas sensing applications. The pure phase V2O5 has been ...subsequently obtained by removing the polymer phase via annealing of the composite fibers in air. The as-spun V2O5/PVAC composite fibers and related products of annealing have been widely studied to characterize their morphological and microstructural properties by TG-DSC, XRD, DRIFT and SEM investigations.
The application of the produced V2O5 fibers as high performance ammonia resistive sensors has been demonstrated. Reversible electrical changes have been observed by exposing V2O5 fibers deposited on interdigited electrodes to sub-ppm concentrations of ammonia gas. The fabricated V2O5 sensor has shown the highest response to ammonia gas at 200–250°C, with a response and recovery time of about 50 and 350s, respectively. A linear dependence of the response value on the ammonia concentration has been observed in the range of 0.85–8.5ppm, with an estimated lower detection limit of about 100ppb.
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