254 research outputs found
ANALYSIS OF THE EFECTS OF AN AC ELECTROMAGNETIC FIELD EXPOSURE IN MICROCIRCULATION OF HUMANS BY USING A 2D LASER SPECKLE FLOWMETRY
To date, there are only a few reports evaluating non-thermal alternating current electromagnetic exposure for medical therapeutic applications. Here, we analyzed the acute effects of hand and forearm exposure to a 50 Hz electromagnetic field (EMF; peak magnetic flux density Bmax 180 mT, Brms 127 mT, 15-min duration of exposure) on cutaneous microcirculation in 11 healthy human subjects (10 males and 1 female, age betwen 22-57 years). The blood flow volume values in the back of the hand were monitored and analyzed using a 2D laser speckle flowmetry. Regional blood flow volume values in sham control exposure were significantly reduced from baseline values during resting conditions. In contrast, the EMF exposure did not significantly decreased the blood flow volume from the baseline values during and after the EMF exposure period. There were significant differences between the EMF and sham exposure groups. Therefore, the EMF exposure significantly prevented the reduction of blood flow volume. Thus, the EMF could improve blood flow volume in cutaneous tissue under ischemic conditions. These findings imply that the physiological role of an EMF-enhanced blood circulation might help eliminate the metabolic waste products including endogenous pain producing substances inducing muscle hardness and pain
Strong interaction studies with kaonic atoms
The strong interaction of antikaons (K-) with nucleons and nuclei in the low
energy regime represents an active research field connected intrinsically with
few-body physics. There are important open questions like the question of
antikaon nuclear bound states - the prototype system being K-pp. A unique and
rather direct experimental access to the antikaon-nucleon scattering lengths is
provided by precision X-ray spectroscopy of transitions in low-lying states of
light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment
at the electron-positron collider DA?NE of LNF-INFN we measured the most
precise values of the strong interaction observables, i.e. the strong
interaction on the 1s ground state of the electromagnetically bound K-p atom
leading to a hadronic shift and a hadronic broadening of the 1s state. The
SIDDHARTA result triggered new theoretical work which achieved major progress
in the understanding of the low-energy strong interaction with strangeness.
Antikaon-nucleon scattering lengths have been calculated constrained by the
SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent
scattering lengths a measurement of the hadronic shift and width of kaonic
deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic
deuterium are in preparation (SIDDHARTA2). Many improvements in the
experimental setup will allow to measure kaonic deuterium which is challenging
due to the anticipated low X-ray yield. Especially important are the data on
the X-ray yields of kaonic deuterium extracted from a exploratory experiment
within SIDDHARTA.Comment: Proc. Few Body 21, 4 pages, 2 figure
New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)
The Pauli exclusion principle (PEP) represents one of the basic principles of
modern physics and, even if there are no compelling reasons to doubt its
validity, it still spurs a lively debate, because an intuitive, elementary
explanation is still missing, and because of its unique stand among the basic
symmetries of physics. A new limit on the probability that PEP is violated by
electrons was estabilished by the VIP (VIolation of the Pauli exclusion
principle) Collaboration, using the method of searching for PEP forbidden
atomic transitions in copper. The preliminary value, {1/2}\beta^{2} \textless
4.5\times 10^{-28}, represents an improvement of about two orders of magnitude
of the previous limit. The goal of VIP is to push this limit at the level of
.Comment: submitted to Journal of Physics: Conference Series, by the Institute
of Physic
The DEAR experiment on DAΦNE
DEAR is one of the first experiments at the new DAΦNE Ø-factory at the Laboratori Nazionali di Frascati dell'INFN. The objective of the DEAR experiment is to perform a precision measurement of the strong interaction shifts and widths of the K-series lines in kaonic hydrogen and the first observation of the same quantities in kaonic deuterium. The aim is to obtain a precise determination of the isospin-dependent kaon-nucleon scattering lengths which will represent a breakthrough in KN low-energy phenomenology and will allow us to determine the kaon-nucleon sigma terms. The sigma terms give a direct measurement of chiral symmetry breaking and are connected to the strangeness content of the proton. First results on background measurements with the DEAR NTP setup installed on DAΦNE are reported
X-ray transition yields of low-Z kaonic atoms produced in Kapton
The X-ray transition yields of kaonic atoms produced in Kapton polyimide
(C22H10N2O5) were measured for the first time in the SIDDHARTA experiment.
X-ray yields of the kaonic atoms with low atomic numbers (Z = 6, 7, and 8) and
transitions with high principal quantum numbers (n = 5-8) were determined. The
relative yield ratios of the successive transitions and those of
carbon-to-nitrogen (C:N) and carbon-to-oxygen (C:O) were also determined. These
X-ray yields provide important information for understanding the capture ratios
and cascade mechanisms of kaonic atoms produced in a compound material, such as
Kapton.Comment: Accepted in Nucl. Phys. A (2013
Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAFNE
The study of the KbarN system at very low energies plays a key role for the
understanding of the strong interaction between hadrons in the strangeness
sector. At the DAFNE electron-positron collider of Laboratori Nazionali di
Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the
low-energy charged kaons from Phi-mesons decaying nearly at rest. The SIDDHARTA
experiment used X-ray spectroscopy of the kaonic atoms to determine the
transition yields and the strong interaction induced shift and width of the
lowest experimentally accessible level (1s for H and D and 2p for He). Shift
and width are connected to the real and imaginary part of the scattering
length. To disentangle the isospin dependent scattering lengths of the
antikaon-nucleon interaction, measurements of Kp and of Kd are needed. We
report here on an exploratory deuterium measurement, from which a limit for the
yield of the K-series transitions was derived: Y(K_tot)<0.0143 and
Y(K_alpha)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium
experiment is introduced.Comment: Accepted by Nuclear Physics
-series X-ray yield measurement of kaonic hydrogen atoms in a gaseous target
We measured the -series X-rays of the exotic atom in the
SIDDHARTA experiment with a gaseous hydrogen target of 1.3 g/l, which is about
15 times the of hydrogen gas. At this density, the absolute
yields of kaonic X-rays, when a negatively charged kaon stopped inside the
target, were determined to be 0.012 for and
0.043 for all the -series transitions . These
results, together with the KEK E228 experiment results, confirm for the first
time a target density dependence of the yield predicted by the cascade models,
and provide valuable information to refine the parameters used in the cascade
models for the kaonic atoms.Comment: 9 pages, 5 figures. Submitted to Nuclear Physics A, Special Issue on
Strangeness and Char
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