424 research outputs found
A Statistical Study of Photospheric Magnetic Field Changes During 75 Solar Flares
Abrupt and permanent changes of photospheric magnetic fields have been
observed during solar flares. The changes seem to be linked to the
reconfiguration of magnetic fields, but their origin is still unclear. We
carried out a statistical analysis of permanent line-of-sight magnetic field
() changes during 18 X-, 37 M-, 19 C- and 1 B-class flares using
data from Solar Dynamics Observatory/Helioseismic and Magnetic Imager. We
investigated the properties of permanent changes, such as frequency, areas, and
locations. We detected changes of in 59/75 flares. We find that
strong flares are more likely to show changes, with all flares M1.6
exhibiting them. For weaker flares, permanent changes are observed in 6/17
C-flares. 34.3\% of the permanent changes occurred in the penumbra and 18.9\%
in the umbra. Parts of the penumbra appeared or disappeared in 23/75 flares.
The area where permanent changes occur is larger for stronger flares. Strong
flares also show a larger change of flux, but there is no dependence of the
magnetic flux change on the heliocentric angle. The mean rate of change of
flare-related magnetic field changes is 20.7 Mx cm min. The
number of permanent changes decays exponentially with distance from the
polarity inversion line. The frequency of the strength of permanent changes
decreases exponentially, and permanent changes up to 750 Mx cm were
observed. We conclude that permanent magnetic field changes are a common
phenomenon during flares, and future studies will clarify their relation to
accelerated electrons, white light emission, and sunquakes to further
investigate their origin.Comment: Piblished in Ap
Noncommutative Chiral Gauge Theories on the Lattice with Manifest Star-Gauge Invariance
We show that noncommutative U(r) gauge theories with a chiral fermion in the
adjoint representation can be constructed on the lattice with manifest
star-gauge invariance in arbitrary even dimensions. Chiral fermions are
implemented using a Dirac operator which satisfies the Ginsparg-Wilson
relation. A gauge-invariant integration measure for the fermion fields can be
given explicitly, which simplifies the construction as compared with lattice
chiral gauge theories in ordinary (commutative) space-time. Our construction
includes the cases where continuum calculations yield a gauge anomaly. This
reveals a certain regularization dependence, which is reminiscent of parity
anomaly in commutative space-time with odd dimensions. We speculate that the
gauge anomaly obtained in the continuum calculations in the present cases can
be cancelled by an appropriate counterterm.Comment: 23 pages, 1 figure. LaTeX, epsf. v3: Reference added and typos
corrected. Final version published in Journal of High Energy Physic
High-resolution Smoothed Particle Hydrodynamics simulations of the merger of binary white dwarfs
We present the results of a set of high-resolution simulations of the merging
process of two white dwarfs. In order to do so, we use an up-to-date Smoothed
Particle Hydrodynamics code which incorporates very detailed input physics and
an improved treatment of the artificial viscosity. Our simulations have been
done using a large number of particles (4x10^5) and cover the full range of
masses and chemical compositions of the coalescing white dwarfs. We also
compare the time evolution of the system during the first phases of the
coalescence with that obtained using a simplified treatment of mass transfer,
we discuss in detail the characteristics of the final configuration, we assess
the possible observational signatures of the merger, like the associated
gravitational waveforms and the fallback X-ray flares, and we study the
long-term evolution of the coalescence.Comment: 14 pages, 9 figures. Accepted for publication in Astronomy and
Astrophysic
Thermodynamics of D0-branes in matrix theory
We examine the matrix theory representation of D0-brane dynamics at finite
temperature. In this case, violation of supersymmetry by temperature leads to a
non-trivial static potential between D0-branes at any finite temperature. We
compute the static potential in the 1-loop approximation and show that it is
short-ranged and attractive. We compare the result with the computations in
superstring theory. We show that thermal states of D0-branes can be reproduced
by matrix theory only when certain care is taken in integration over the moduli
space of classical solutions in compactified time.Comment: 13 pages, 1 figur
Comparison between Poaceae Airborne Pollen Counts and Phl p5 Aeroallergen Quantification in South Europe
The European project HIALINE: Comparison between Poaceae Airborne Pollen Counts and Phl p5 Aeroallergen Quantification in South Europe
C. Antunes1,2, R. Ferro2, R. Ribeiro2, Torres M.C.4, M.J. Velasco4H. García-Mozo4, Galán, C4 , R.Brandao1,3, M.Thibaudon5, R. Albertini6 Ugolotti. M.6, Usberti I.6, Dall’Aglio P.6 and the HIALINE team7
1DInstitute of Mediterranean Agricultural and Environmental Sciences –ICAAM, University of Évora, Portugal
2Department of Chemistry, University of Évora, Portugal
3Department of Biology, University of Évora, Portugal
4Department of Botany, Ecology and Plant Physiology, University of Córdoba
5Réseau National de l Surveillance Aerobiologique, Saint-Genis-l’Argentière, France
6Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Italy
7J.T.M. Buters, Germany, M. Thibaudon, France, M. Smith, Great Britain, C. Galan, Spain, R. Brandao and C.M. Antunes, Portugal, G. Reese, Germany, R. Albertini, Italy, L. Grewling, Poland, A. Rantio-Lehtimäki, Finland, S. Jäger and U. Berger, Austria, I. Sauliene, Lithuania, L. Cecchi, Italy
Introduction: Nowadays, pollinosis is affecting a large percentage of population in countries with a western life style. The existence of allergenic activity in the atmosphere is not only associated to pollen grains and fungal spores, but also to submicronic and paucimicronic biological particles. The origin of these allergens can be due to the rupture of pollen transported in the atmosphere or to the presence of allergens from other parts of the plant making amorphous material with an allergen load. Poaceae pollen is recognized as one of the main causes of allergic disease in all Europe. In this study we have tried to compare Poaceae pollen counts in the air and Phl p 5, one of the major allergens of this family, through the use of a high-volume cascade impactor (Chemvol). This study was done in the frame of the European project HIALINE and it compares the results obtained in 2009 by 4 different partners participating in this project: in Córdoba (Spain), Évora (Portugal), Lyon (France) and Parma (Italy).
Methodology: Pollen grains were sampled using a 7-day volumetric Hirst type spore trap. Chemvol high-volume cascade impactor equipped with stages PM>10µm, 10 µm>PM>2.5µm was used for detecting aeroallergens. In each stage polyurethane filters were use as an impacting substrate. Phl p 5 allergen was determined using an allergen specific ELISA. Antibodies for analysis were delivered by Allergopharma Joachim Ganzer KG, the industrial partner in this project. At each location both samplers were placed side-by-side.
Results: Most of the allergen was collected in the PM>10µm fraction. Similar profiles between airborne pollen and the total allergenic load was observed during the pollen season. A good correlation was obtained between pollen count and allergen content of the air and a value of 2.5 pg/pollen grain of Poaceae was estimated.
Discussion: This is the first year of this project. Nevertheless, results suggest that the allergenic load in outdoor air might be mainly due to pollen bursts. It supports the hypothesis that monitoring the allergens itself in ambient air might be an improvement in allergen exposure assessment.
This work was supported in part by the European Agency for Health and Consumers EAHC, Luxembourg, under the grant agreement 2008110
Comparison between Airborne Pollen and Aeroallergen Quantification with the ChemVol Impact Sampler. Olive pollen vs Ole e 1
Comparison between Airborne Pollen and Aeroallergen Quantification with the ChemVol Impact Sampler. Olive pollen vs Ole e 1.
Torres M.C.1, C. Antunes2, M.J. Velasco1, R. Ferro2, H. García-Mozo1, R. Ribeiro2, R.Brandao3, Galán, C1 and the HIALINE team4
1Department of Botany, Ecology and Plant Physiology, University of Córdoba
2Department of Chemistry, University of Évora, Portugal
3Department of Biology, University of Évora, Portugal
4J.T.M. Buters, Germany, M. Thibaudon, France, M. Smith, Great Britain, C. Galan, Spain, R. Brandao and C. Antunes, Portugal, G. Reese, Germany, R. Albertini, Italy, L. Grewling, Poland, A. Rantio-Lehtimäki, Finland, S. Jäger and U. Berger, Austria, I. Sauliene, Lithuania, L. Cecchi, Italy
Nowadays, pollinosis is affecting a large percentage of population in the countries with a western life style. The existence of allergenic activity in the atmosphere is not only associated to pollen grains and fungal spores, but also to submicronic and paucimicronic biological particles. The origin of these allergens can be due to the rupture of pollen transported in the atmosphere or to the presence of allergens from other parts of the plant making amorphous material with an allergen load.
Olive pollen is recognized as one of the main causes of allergic disease in the Mediterranean area. In this study we have tried to compare olive pollen count in the air and Ole e 1 as major allergen of this species, at two different localities in South of Europe: Evora (Portugal) and Córdoba (Spain). At each location both samplers were placed side-by-side.
Pollen grains have been sampled using a volumetric Hirst type spore trap. Chemvol high-volume cascade impactor equipped with stages PM>10µm, 10 µm>PM>2.5µm were used for detecting aeroallergens. Ole e 1 major allergen was determined using allergen specific ELISA´s.
Similar behaviour between pollen and the total allergenic load was observed during the pollen season. Nevertheless, at some occasions, during the previous and later period of the pollen season, airborne allergenic load was detected in South Spain, due to the contributions from other Oleaceae species. For this reason the use of these two different methodologies allow a better understanding of the allergenic load in the atmosphere.
This work was supported in part by the European Agency for Health and Consumers EAHC, Luxembourg, under the grant agreement 20081107
The European project HIALINE: Comparison between Poaceae Airborne Pollen Counts and Phl p5 Aeroallergen Quantification in SW Europe
The European project HIALINE: Comparison between Poaceae Airborne Pollen Counts and Phl p5 Aeroallergen Quantification in SW Europe
C. Antunes1*, R. Ferro1, R. Ribeiro1, Torres M.C.3, M.J. Velasco3H. García-Mozo3, Galán, C3 , R.Brandao2, M.Thibaudon4 and the HIALINE team5
1Department of Chemistry, University of Évora, Portugal
2Department of Biology, University of Évora, Portugal
3Department of Botany, Ecology and Plant Physiology, University of Córdoba
4Réseau National de l Surveillance Aerobiologique, Saint-Genis-l’Argentière, France
5J.Buters, Germanny, M. Thibaudon, France, M. Smith, Great Britain, C. Galan, Spain, R. Brandao and C.M. Antunes, Portugal, R. Albertini, Italy, L. Grewling, Poland, A. Rantio-Lehtimäki, Finland, S. Jäger and U. Berger, Austria, I. Sauliene, Lithuania, L. Cecchi, Italy
* Presenting Author:
Antunes, C. Department of Chemistry, University of Évora, Portugal.
Phone +351 266745319 ; email: [email protected]
Introduction: Nowadays, pollinosis is affecting in a large percentage of population in the developed countries. The existence of allergenic activity in the atmosphere is not only associated to pollen grains and fungal spores, but also to submicronic and paucimicronic biological particles. The origin of these allergens can be due to the rupture of pollen transported in the atmosphere or to the presence of allergens from other parts of the plant making amorphous material with allergenic load. Poaceae pollen is recognized as one of the main causes of allergic disease in all Europe. In this study we have tried to compare Poaceae pollen counts in the air and Phl p 5, one of the major allergens of this family, through the use of a high-volume cascade impactor (Chemvol). This study was done in the frame of the European project HIALINE and it compares the results obtained in 2009 by 3 different partners participating in this project: in Córdoba (Spain), Évora (Portugal) and Lyon (France).
Methodology: Pollen grains have been taken out using a 7-day volumetric Hirst type spore trap. Chemvol high-volume cascade impactor equipped with stages PM>10µm, 10 µm>PM>2.5µm were used for detecting aeroallergens. In each stage polyurethane filters were applied. Phl p5 allergen was determined using allergen specific ELISA´s. Antibodies for analysis are delivered by Allergopharma Joachim Ganzer KG, the industrial partner in this project. Both samplers were placed side-by-side.
Results: Most of the allergen was collected in the PM>10µm fraction. Similar profiles between airborne pollen and the total allergenic load was observed during the pollen season. A good correlation was obtained and a value of 2.5 pg/pollen grain of Poaceae was estimated.
Discussion: These results suggest that the allergenic load in outdoor air might be mainly due to pollen bursts. It supports the hypothesis that monitoring the allergens itself in ambient air might be an improvement in allergen exposure assessment.
This work was supported in part by the European Agency for Health and Consumers EAHC, Luxembourg, under the grant agreement 2008110
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