1,052 research outputs found
1.65 micrometers (H-band) surface photometry of galaxies. III: observations of 558 galaxies with the TIRGO 1.5m telescope
We present near-infrared H-band (1.65 micron) surface photometry of 558
galaxies in the Coma Supercluster and in the Virgo cluster. This data set,
obtained with the Arcetri NICMOS3 camera ARNICA mounted on the Gornergrat
Infrared Telescope, is aimed at complementing, with observations of mostly
early-type objects, our NIR survey of spiral galaxies in these regions,
presented in previous papers of this series. Magnitudes at the optical radius,
total magnitudes, isophotal radii and light concentration indices are derived.
We confirm the existence of a positive correlation between the near-infrared
concentration index and the galaxy H-band luminosity. (Tables 1 and 2 are only
available in electronic form upon request to [email protected])Comment: 12 pages, 6 figures. Accepted for publication in A&A
Genotoxicity testing for radon exposure: Dolichopoda (Orthoptera, Rhaphidophoridae) as potential bio-indicator of confined environments
Abstract
Radon represents the major source of natural radioactivity in confined environments. Despite the clear evidence of a direct association between residential exposure and human lung cancer provided by case-control studies, results relating indoor exposure and genotoxic/mutagenic effect induction are still contradictory. The present study attempts to estimate the genotoxic effects induced by exposure to radioactive radon in wild cricket populations sampled from caves where varying concentrations of radon are present. Cave crickets are also tested as possible bio-indicator organisms of genotoxic potential of contaminated residential and confined environments. Six caves in Central Italy are considered covering a broad spectrum of radon radioactivity concentration (221â26, 000 Bq/m3). Dolichopoda specimens were sampled from each cave; both haemocytes and brain cells taken from individuals were tested for responsiveness to DNA damage induced by radon through the Comet assay. Specimens from the least radioactive cave, housed in controlled conditions for 60 days before analysis, were used as control group. Statistically significant increase of DNA damage was found in all groups of individuals from each cave, for both cell types. Very low values of all Comet parameters were found in control group individuals, which gave indications of a good responsiveness of the organism to the variable environmental levels of radioactive contamination. Results indicate that cave crickets represent a reliable tool for the detection of genotoxic potential induced by radioactive contamination of confined environments and can be proposed as a possible bio-indicator system for air (-radioactive) pollution related to indoor exposure
1.65 micrometers (H-band) surface photometry of galaxies. IV:observations of 170 galaxies with the Calar Alto 2.2m telescope
We present near-infrared (H band) surface photometry of 170 galaxies,
obtained in 1997 using the Calar Alto 2.2m telescope equipped with the NICMOS3
camera MAGIC. The majority of our targets are selected among bright members of
the Virgo cluster, however galaxies in the A262 and Cancer clusters and in the
Coma/A1367 supercluster are also included. This data set is aimed at
complementing the NIR survey in the Virgo cluster discussed in Boselli et al.
(1997) and in the Coma Supercluster, presented in Papers I, II and III of this
series. Magnitudes at the optical radius, total magnitudes, isophotal radii and
light concentration indices are derived. (Tables 1 and 2 are only available in
electronic form upon request to [email protected])Comment: 11 pages, 6 figures. Accepted for publication in A&A
The NearâInfrared Îș-Space of Early and Late Type Galaxies
We present the nearâinfrared (Hâband: λ = 1.65 ÎŒm) Îșâspace (Îș1 â log M, Îș2 â log Ie, Îș3 â log M/L) of high surfaceâbrightness early and late type galaxies, based on a sample of 419 objects optically selected in regions of the A262, Cancer, and Virgo clusters and of the Coma Supercluster. We discuss the distribution of the pressureâsupported and rotationallyâsupported systems within this space and the ensuing scaling relations. We analyze the link between galaxy structure and star formation history through a comparison of the loci occupied by galaxies of the Local Universe in both the nearâinfrared (this work) and optical Îșâspaces. Our results support scenarios of galaxy formation and evolution with the following fundamental ingredients: collapsing protoâgalactic systems are characterized by i) a bimodal distribution in mass and angular momentum; and by ii) a massâdependent characteristic star formation time scale
Constraining the ages of the fireballs in the wake of the dIrr galaxy VCC1217 / IC3418
A complex of Halpha emitting blobs with strong FUV excess is associated to
the dIrr galaxy VCC1217 / IC3418 (Hester et al. 2010), and extends up to 17 Kpc
in the South-East direction. These outstanding features can be morphologically
divided into diffuse filaments and compact knots, where most of the star
formation activity traced by Halpha takes place. We investigate the properties
of the galaxy and the blobs using a multiwavelength approach in order to
constrain their origin. We collect publicly available data in UV and Halpha and
observe the scene in the optical U,g,r,i bands with LBT. The photometric data
allows to evaluate the star formation rate and to perform a SED fitting
separately of the galaxy and the blobs in order to constrain their stellar
population age. Moreover we analyze the color and luminosity profile of the
galaxy and its spectrum to investigate its recent interaction with the Virgo
cluster. Our analysis confirms that the most plausible mechanism for the
formation of the blobs is ram pressure stripping by the Virgo cluster IGM. The
galaxy colors, luminosity profile and SED are consistent with a sudden gas
depletion in the last few hundred Myr. The SED fitting of the blobs constrains
their ages in < 400 Myr.Comment: 10 pages, 11 figures, accepted for publication in Astronomy and
Astrophysic
From wheat sourdough to gluten-free sourdough: a conventional process for producing gluten-free bread
Gluten-free (GF) sourdough was prepared from wheat sourdough and analysed both in fresh (GFS) and dried forms (DGFS). The gluten content in each GF sourdough sample was <20mgkg(-1). The dough leavening capacity and the properties of the bread samples were investigated and compared to those of bread prepared using bakery yeast (Saccharomyces cerevisiae). Two commercial rice-based mixtures (different for the presence/absence of buckwheat flour) were used to prepare bread samples. In GFS, lactic acid bacteria (LAB) and yeasts were found in amounts corresponding to 10(8) and 10(7) CFUg(-1), respectively, whereas both LAB and yeasts were detected in lower amounts (about 10(6) CFUg(-1)) in DGFS. When used in bread-making, both GFS types produced significant dough acidification and exhibited good dough development during proofing, resulting in loaves with specific volume values between 3.00 and 4.12mLg(-1), values similar to those obtained for reference bread (3.05 divided by 4.15mLg(-1)). The use of GFS was effective in lowering the bread staling rate during storage for up to 7days
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- malsâ 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
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