8,351 research outputs found
Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale
We present a study of the HII regions in the galaxy NGC 6754 from a two
pointing mosaic comprising 197,637 individual spectra, using Integral Field
Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science
Verification program. The data cover the entire galaxy out to ~2 effective
radii (re ), sampling its morphological structures with unprecedented spatial
resolution for a wide-field IFU. A complete census of the H ii regions limited
by the atmospheric seeing conditions was derived, comprising 396 individual
ionized sources. This is one of the largest and most complete catalogue of H ii
regions with spectroscopic information in a single galaxy. We use this
catalogue to derive the radial abundance gradient in this SBb galaxy, finding a
negative gradient with a slope consistent with the characteristic value for
disk galaxies recently reported. The large number of H ii regions allow us to
estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong
constraints on the proposed mechanisms for metal mixing in disk galaxies, like
radial movements associated with bars and spiral arms, when comparing with
simulations. We found evidence for an azimuthal variation of the oxygen
abundance, that may be related with the radial migration. These results
illustrate the unique capabilities of MUSE for the study of the enrichment
mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&
Sandfly saliva of Lutzomyia ovallesi (Diptera: Psychodidae) as a possible marker for the transmission of Leishmania in Venezuela Andes region
Background & objectives: The saliva of the Phlebotominae is highly immunogenic to the vertebrate host and isa determining factor in the Leishmania infection. The aim of this work was to study the saliva of Lutzomyiaovallesi as a possible risk marker for the transmission of Leishmania.Methods: Two populations of L. ovallesi from different geographical areas and subjected to different environmentalconditions were compared by geometric morphometry of the wings, by protein profile analysis of salivary glandsand by assessing the presence of anti-saliva protein in human sera confronted with laboratory L. ovallesi saliva.Results: The results showed differences in the isometric size and structure of the wings but no allometric effects.Protein profiles of salivary glands of both the L. ovallesi populations studied were found to be similar, based on11 protein bands with molecular weights ranging from 16 to 99 kDa. Anti-saliva antibodies were present inhuman sera, but human sera infected and uninfected with leishmaniasis could not be differentiated.Interpretation & conclusion: We conclude that the saliva of laboratory-reared L. ovallesi is representative ofthat of the wild population. It is suggested to study the presence of anti-saliva antibodies in other species ofsandflies and mosquitoe
Present and future of the OTELO project
OTELO is an emission-line object survey carried out with the red tunable
filter of the instrument OSIRIS at the GTC, whose aim is to become the deepest
emission-line object survey to date. With 100% of the data of the first
pointing finally obtained in June 2014, we present here some aspects of the
processing of the data and the very first results of the OTELO survey. We also
explain the next steps to be followed in the near future.Comment: Oral contribution presented in the XI Scientific Meeting of the
Spanish Astronomical Society held on September 8-12, in Teruel, Spain (7
pages, 2 figures, 1 table). To appear in Highlights of Spanish Astrophysics
VIII, Proceedings of the XI Scientific Meeting of the Spanish Astronomical
Society. Eds. A. J. Cenarro, F. Figueras, C. Hern\'andez-Monteagudo, J.
Trujillo, L. Valdiviels
Resonance phenomena of a solitonlike extended object in a bistable potential
We investigate the dynamics of a soliton that behaves as an extended
particle. The soliton motion in an effective bistable potential can be chaotic
in a similar way as the Duffing oscillator. We generalize the concept of
geometrical resonance to spatiotemporal systems and apply it to design a
nonfeedback mechanism of chaos control using localized perturbations.We show
the existence of solitonic stochastic resonance.Comment: 3 postscript figure
OTELO survey: optimal emission-line flux determination with OSIRIS/GTC
Emission-line galaxies are important targets for understanding the chemical
evolution of galaxies in the universe. Deep, narrow-band imaging surveys allow
to detect and study the flux and the equivalent widths (EW) of the emission
line studied. The present work has been developed within the context of the
OTELO project, an emission line survey using the Tunable Filters (TF) of
OSIRIS, the first generation instrument on the GTC 10.4m telescope located in
La Palma, Spain, that will observe through selected atmospheric windows
relatively free of sky emission lines. With a total survey area of 0.1 square
degrees distributed in different fields, reaching a 5 \sigma depth of 10^-18
erg/cm^2/s and detecting objects of EW < 0.3 A, OTELO will be the deepest
emission line survey to date. As part of the OTELO preparatory activities, the
objective of this study is to determine the best combination of sampling and
full width at half maximum (FWHM) for the OSIRIS tunable filters for deblending
H\alpha from [NII] lines by analyzing the flux errors obtained. We simulated
the OTELO data by convolving a complete set of synthetic HII galaxies in EW
with different widths of the OSIRIS TFs. We estimated relative flux errors of
the recovered H\alpha and [NII]6583 lines. We found that, for the red TF, a
FWHM of 12 A and a sampling of 5 A is an optimal combination that allow
deblending H\alpha from the [NII]6583 line with a flux error lower than 20%.
This combination will allow estimating SFRs and metallicities using the H\alpha
flux and the N2 method, respectively.Comment: 16 pages, 9 figures. Some authors added. Accepted for publication in
PAS
Proceedings of the 8th World Congress on Conservation Agriculture
Under the banner: The Future of Farming – Profitable and Sustainable Farming with
Conservation Agriculture, the 8WCCA highlighted the global contribution of Conservation Agriculture towards achieving these outcomes. It also explored how CA land use can help to address humankind’s major global challenges of climate change, environmental degradation and food security
while safeguarding the livelihoods of small and large-scale farmers. The proven benefits of CA in terms of erosion control, carbon sequestration, biodiversity regeneration, and improved water and nutrient cycling are all contributing to the achievement of the manifold objectives of the international conventions and agreements including the
Sustainable Development Goals, European
Green Deal and F2F Strategy
Emitters of -photon bundles
We propose a scheme based on the coherent excitation of a two-level system in
a cavity to generate an ultrabright CW and focused source of quantum light that
comes in groups (bundles) of photons, for an integer tunable with the
frequency of the exciting laser. We define a new quantity, the \emph{purity} of
-photon emission, to describe the percentage of photons emitted in bundles,
thus bypassing the limitations of Glauber correlation functions. We focus on
the case and show that close to 100% of two-photon emission and
90% of three-photon emission is within reach of state of the art cavity QED
samples. The statistics of the bundles emission shows that various
regimes---from -photon lasing to -photon guns---can be realized. This is
evidenced through generalized correlation functions that extend the standard
definitions to the multi-photon level.Comment: Introduce the n-th order N-photon correlation functions. Reorganized
to emphasize the N-photon emitter, now extended to the antibunching regime,
rather than only coherent emission as previsoul
Percepción de los riesgos asociados a la pérdida auditiva inducida por ruido. Estado del arte y diseño de herramientas interactivas para formación y concienciación
La exposición al ruido en el puesto de trabajo y la pérdida auditiva inducida por ruido se encuentran estrechamente relacionadas con las actitudes que tienen de los trabajadores sobre el uso de los dispositivos de protección auditiva. En estudios previos se ha demostrado que los trabajadores son reacios a su utilización por diferentes motivos: desconocimiento de los efectos que produce el ruido sobre la salud auditiva, dificultades para utilizarlos de forma correcta, incomodidad, etc. Con el objetivo de mejorar las actitudes de los trabajadores ante el uso de dispositivos de protección auditiva se llevó a cabo un estudio bibliográfico sobre los factores que influyen en la conducta de los trabajadores ante el uso de protectores auditivos, así como su conocimiento sobre los riesgos asociados. Una vez analizados los antecedentes y las actuales necesidades, se desarrollaron herramientas interactivas de fácil utilización para mejorar la concienciación de los trabajadores sobre este aspecto. Se presenta la revisión bibliográfica sobre el uso de protectores auditivos, un análisis de los diferentes enfoques comúnmente utilizados para formación y concienciación de trabajadores sobre los riesgos derivados de la pérdida auditiva inducida por ruido y finalmente las herramientas desarrolladas como propuesta para mejorar la percepción de dicho riesgo entre los trabajadores
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