1,030 research outputs found
EZ: A Tool for Automatic Redshift Measurement
We present EZ (Easy redshift), a tool we have developed within the VVDS
project to help in redshift measurement from otpical spectra. EZ has been
designed with large spectroscopic surveys in mind, and in its development
particular care has been given to the reliability of the results obtained in an
automatic and unsupervised mode. Nevertheless, the possibility of running it
interactively has been preserved, and a graphical user interface for results
inspection has been designed. EZ has been successfully used within the VVDS
project, as well as the zCosmos one. In this paper we describe its architecture
and the algorithms used, and evaluate its performances both on simulated and
real data. EZ is an open source program, freely downloadable from
http://cosmos.iasf-milano.inaf.it/pandora.Comment: accepted for publication in Publications of the Astronomical Society
of the Pacifi
El bicentenario desde los hospitales de la UBA
Fil: Abbate, Eduardo H. Universidad de Buenos Aires. Facultad de Medicina. Instituto de TisioneumonologĂa Prof. Dr. RaĂşl F. Vaccarezza; Argentina.Instituto de oncologĂa Angel Roffo: \nExcelencia mĂ©dica en la lucha contra el cáncer. Instituto de investigaciones mĂ©dicas Alfredo Lanari: \nCincuenta años formando mĂ©dicos de la UBA. Instituto de tisioneumonologĂa RaĂşl F. Vaccarezza: \nCiencia al servicio de la lucha contra la tuberculosis. Hospital de ClĂnicas JosĂ© de San MartĂn: \nLa medicina en la RevoluciĂłn de Mayo de 1810
Population assessment without individual identification using camera-traps: a comparison of four methods
The use of camera traps to estimate population size when animals are not individually recognizable is gaining traction in the ecological literature, because of its applicability in population conservation and management. We estimated population size of synthetic animals with four camera trap sampling-based statistical models that do not rely on individual recognition. Using a realistic model of animal movement to generate synthetic data, we compared the random encounter model, the random encounter and staying time model, the association model and the time-to-event-model and we investigated the impact of violation of assumptions on the population size estimates. While under ideal conditions these models provide reliable population estimates, when synthetic animal movements were characterised by differences in speed (due to diverse behaviours such as locomotion, grazing and resting) none of the model provided both unbiased and precise density estimates. The random encounter model and the time-to-event-model provided pre- cise results but tended to overestimate population size, while the random encounter and staying time model was less precise and tended to underestimate population size. Lastly, the association model was unable to provide precise results. We found that each tested model was very sensitive to the method used to estimate the range of the field-of-view of camera traps. Density esti- mates from both random encounter model and time-to-event-model were also very sensitive to biases in the estimate of ani- mals’ speed. We provide guidelines on how to use these statistical models to get population size estimates that could be useful to wildlife managers and practitioners
Post-Depositional Biodegradation Processes of Pollutants on Glacier Surfaces
Glaciers are important fresh-water reservoirs for our planet. Although they are often
located at high elevations or in remote areas, glacial ecosystems are not pristine, as many pollutants
can undergo long-range atmospheric transport and be deposited on glacier surface, where they
can be stored for long periods of time, and then be released into the down-valley ecosystems.
Understanding the dynamics of these pollutants in glaciers is therefore important for assessing their
environmental fate. To this aim, it is important to study cryoconite holes, small ponds filled with
water and with a layer of sediment, the cryoconite, at the bottom, which occur on the surface of
most glaciers. Indeed, these environments are hotspots of biodiversity on glacier surface as they host
metabolically active bacterial communities that include generalist taxa able to degrade pollutants.
In this work, we aim to review the studies that have already investigated pollutant (e.g., chlorpyrifos
and polychlorinated-biphenyls (PCBs)) degradation in cryoconite holes and other supraglacial
environmental matrices. These studies have revealed that bacteria play a significant role in pollutant
degradation in these habitats and can be positively selected in contaminated environments. We will
also provide indication for future research in this field
Euclid Space Mission: building the sky survey
The Euclid space mission proposes to survey 15000 square degrees of the
extragalactic sky during 6 years, with a step-and-stare technique. The
scheduling of observation sequences is driven by the primary scientific
objectives, spacecraft constraints, calibration requirements and physical
properties of the sky. We present the current reference implementation of the
Euclid survey and on-going work on survey optimization.Comment: to appear in Proceedings IAU Symposium No. 306, "Statistical
Challenges in 21st Century Cosmology", A.F. Heavens, J.-L. Starck & A.
Krone-Martins, ed
Witnessing galaxy preprocessing in the local Universe: the case of a star-bursting group falling into Abell 1367
We present a multiwavelength analysis of a compact group of galaxies
infalling at high speed into the dynamically young cluster Abell 1367. Peculiar
morphologies and unusually high Halpha emission are associated with two giant
galaxies and at least ten dwarfs/extragalactic HII regions, making this group
the region with the highest density of star formation activity ever observed in
the local clusters. Moreover Halpha imaging observations reveal extraordinary
complex trails of ionized gas behind the galaxies, with projected lengths
exceeding 150 kpc. These unique cometary trails mark the gaseous trajectory of
galaxies, witnessing their dive into the hot cluster intergalactic medium.
Under the combined action of tidal forces among group members and the
ram-pressure by the cluster ambient medium, the group galaxies were fragmented
and the ionized gas was blown out. The properties of this group suggest that
environmental effects within infalling groups may have represented a
preprocessing step of the galaxy evolution during the high redshift cluster
assembly phase.Comment: 23 pages, 13 figures, 5 table. Accepted for publication in Astronomy
& Astrophysics main journal. Version with high-resolution images available at
http://goldmine.mib.infn.it/papers/preprocessing.htm
UV Dust Attenuation in Star-forming Galaxies: II Calibrating the A(UV) vs. L_TIR/L_UV relation
We investigate the dependence of the total-infrared (TIR) to UV luminosity
ratio method for calculating the UV dust attenuation A(UV) from the age of the
underlying stellar populations by using a library of spectral energy
distributions for galaxies with different star formation histories. Our
analysis confirms that the TIR/UV vs. A(UV) relation varies significantly with
the age of the underlying stellar population: i.e. for the same TIR/UV ratio,
systems with low specific star formation rate (SSFR) suffer a lower UV
attenuation than starbursts. Using a sample of nearby field and cluster spiral
galaxies we show that the use of a standard (i.e. age independent) TIR/UV vs.
A(UV) relation leads to a systematic overestimate up to 2 magnitudes of the
amount of UV dust attenuation suffered by objects with low SSFR and in
particular HI-deficient star forming cluster galaxies. This result points out
that the age independent vs. relation cannot be used to study
the UV properties of large samples of galaxies including low star-forming
systems and passive spirals. Therefore we give some simple empirical relations
from which the UV attenuation can be estimated taking into account its
dependence on the age of the stellar populations, providing a less biased view
of UV properties of galaxies.Comment: 16 pages, 10 figures, 6 tables. Accepted for publication on MNRAS
main journal. High resolution version and tables also available at
http://www.astro.cf.ac.uk/pub/Luca.Cortese/UVattenuation.htm
Wheat germ stabilization by heat-treatment or sourdough fermentation: effects on dough rheology and bread properties
The aim of this work was to evaluate the effects of wheat germ - stabilized by toasting or by sourdough fermentation - on dough and bread properties. Doughs were produced by adding increasing amounts of each type of stabilized germ, starting with the current recommended level of 3 g/100 g up to 20 g/100 g. Sourdough fermentation ensured the presence of lactic acid bacteria (LAB) in amounts comparable to those found in conventional sourdough. The acidification induced by LAB inactivates lipase and lipoxygenase, as does the toasting process. These results account for the decrease in rancidity, as demonstrated by the low development of hexanal during storage. Fermentation significantly decreased the content of glutathione, responsible for the deterioration of the rheological characteristics and workability of dough containing high levels of germ. Dough enriched with fermented germ exhibited high stability during mixing and development. Positive effects (high specific volume and low firmness) associated with the use of germ stabilized by fermentation have been detected both in fresh bread and in samples stored up to 4 days in controlled conditions of humidity and temperature. Finally, the sensory consumers' test confirmed that the addition of fermented germ did not diminish the liking of the sample
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