6,479 research outputs found
The Wide-field High-resolution Infrared TElescope (WHITE)
The Wide-field High-resolution Infrared TElescope (WHITE) will be dedicated
in the first years of its life to carrying out a few (well focused in terms of
science objectives and time) legacy surveys.
WHITE would have an angular resolution of ~0.3'' homogeneous over ~0.7 sq.
deg. in the wavelength range 1 - 5 um, which means that we will very
efficiently use all the available observational time during night time and day
time. Moreover, the deepest observations will be performed by summing up
shorter individual frames. We will have a temporal information that can be used
to study variable objects.
The three key science objectives of WHITE are : 1) A complete survey of the
Magellanic Clouds to make a complete census of young stellar objects in the
clouds and in the bridge and to study their star formation history and the link
with the Milky Way. The interaction of the two clouds with our Galaxy might the
closest example of a minor merging event that could be the main driver of
galaxy evolution in the last 5 Gyrs. 2) The building of the first sample of
dusty supernovae at z<1.2 in the near infrared range (1-5 um) to constrain the
equation of state from these obscured objects, study the formation of dust in
galaxies and build the first high resolution sample of high redshift galaxies
observed in their optical frame 3) A very wide weak lensing survey over that
would allow to estimate the equation of state in a way that would favourably
compete with space projects.Comment: Invited talk to the 2nd ARENA Conference : "The Astrophysical Science
Cases at Dome C" Potsdam 17-21 September, 200
Nonthermal hard X-ray excess in the Coma cluster: resolving the discrepancy between the results of different PDS data analyses
The detection of a nonthermal excess in the Coma cluster spectrum by two
BeppoSAX observations analyzed with the XAS package (Fusco-Femiano et al.) has
been disavowed by an analysis (Rossetti & Molendi) performed with a different
software package (SAXDAS) for the extraction of the spectrum. To resolve this
discrepancy we reanalyze the PDS data considering the same software used by
Rossetti & Molendi. A correct selection of the data and the exclusion of
contaminating sources in the background determination show that also the SAXDAS
analysis reports a nonthermal excess with respect to the thermal emission at
about the same confidence level of that obtained with the XAS package
(~4.8sigma). Besides, we report the lack of the systematic errors investigated
by Rossetti & Molendi and Nevalainen et al. taking into account the whole
sample of the PDS observations off the Galactic plane, as already shown in our
data analysis of Abell 2256 (Fusco-Femiano, Landi & Orlandini). All this
eliminates any ambiguity and confirms the presence of a hard tail in the
spectrum of the Coma cluster.Comment: 12 pages, 2 figures. Accepted for publication in ApJ Letter
Distance and reddening of the Local Group dwarf irregular galaxy NGC 6822
On the basis of a new photometric analysis of the Local Group dwarf irregular
galaxy NCG 6822 based on observations obtained with the Advanced Camera for
Surveys onboard the Hubble Space Telescope, we have obtained a new estimate of
the extinction of two fields located in the southeast region of the galaxy.
Because of significant differences in the distance estimates to NGC 6822
available in literature, we decided to provide an independent determination of
the distance to this galaxy based on an updated and self-consistent theoretical
calibration of the tip of the red giant branch brightness. As a result we newly
determined the distance to NGC 6822 to be equal to , and compared our measurement with the most recent determinations of this
distance.Comment: 5 pages, 5 figures, Astronomy & Astrophysics (Research Note), in
press (proof correction included
Effect of Ferric Sodium EDTA administration, in combination with vitamin C, folic acid, copper gluconate, zinc gluconate and selenomethionine, on cardiovascular risk evaluation: exploration of the HRV frequency domain
diseases. Using the Heart Rate Variability (HRV) analysis is possible to provide an evaluation of the safety and the
effectiveness of intervention.
Objective: To evaluate the efficacy and safety of Ferric Sodium EDTA in combination with vitamin C, folic acid, copper
gluconate, zinc gluconate and selenomethionine (Ferachel forte®) 2 tabs/day for 24 days in elderly patients with secondary
anaemia, by exploring the HRV frequency domain.
Methods: In 45 elderly patients with secondary anaemia and/or low-moderate kidney failure, laboratory values after
administration of Ferric Sodium EDTA, 2 tabs a day, in combination with vitamin C, folic acid, copper gluconate, zinc
gluconate and selenomethionine (Ferachel forte®) for 24 days (N=16 patients) or ferrous gluconate 63 mg/day added to
saline solution, administered using intravenous access during the hospitalization period of 15 ± 5 days (N=29 patients)
were evaluated. Also, ECG signals and bioelectrical impedance (BIA) were measured.
Results: Oral iron supplementation with Ferric Sodium EDTA, in combination with vitamin C, folic acid, copper gluconate,
zinc gluconate and selenomethionine (Ferachel forte®) confirmed to be effective and safe about the cardiovascular risk
in old patients. This study showed the real superiority of the oral administration about the cardiovascular risk in elderly
patients in comparison with intravenous administration of ferrous gluconate.
Conclusion: This study confirms that Ferric Sodium EDTA combination (Ferachel forte®) can be a valid alternative to ferrous
gluconate intravenous therapy (gold standard) in the treatment of secondary anaemia in elderly patients. In fact, during
the treatment, efficacy results have been maintained without statistically significant variations about cardiovascular risk,
evaluated by exploring the HRV frequency domain
HJ Inequalities Involving Lie Brackets and Feedback Stabilizability with Cost Regulation
With reference to an optimal control problem where the state has to approach asymptotically a closed target while paying a non-negative integral cost, we propose a generalization of the classical dissipative relation that defines a Control Lyapunov Function to a weaker differential inequality. The latter involves both the cost and the iterated Lie brackets of the vector fields in the dynamics up to a certain degree k = 1, and we call any of its (suitably defined) solutions a degree -k Minimum Restraint Function. We prove that the existence of a degree -k Minimum Restraint Function allows us to build a Lie-bracket-based feedback which sample stabilizes the system to the target while regulating (i.e., uniformly bounding) the cost
A state-of-the-art analysis of the dwarf irregular galaxy NGC 6822
We present a detailed photometric study of the dwarf irregular galaxy NGC
6822 aimed at investigating the properties of its stellar populations and, in
particular, the presence of stellar radial gradients. Our goal is to analyse
the stellar populations in six fields, which cover the whole bar of this dwarf
galaxy. We derived the quantitative star formation history (SFH) of the six
fields using the IAC method, involving IAC-pop/MinnIAC codes. The solutions we
derived show an enhanced star formation rate (SFR) in Fields 1 and 3 during the
past 500 Myr. The SFRs of the other fields are almost extinguished at very
recent epochs and. We study the radial gradients of the SFR and consider the
total mass converted into stars in two time intervals (between 0 and 0.5 Gyr
ago and between 0.5 and 13.5 Gyr ago). We find that the scale lengths of the
young and intermediate-to-old populations are perfectly compatible, with the
exception of the young populations in Fields 1 and 3. The recent SF in these
two fields is greater than in the other ones. This might be an indication that
in these two fields we are sampling incipient spiral arms. Further evidence and
new observations are required to prove this hypothesis. In addition, we derived
the age-metallicity relations. As expected, the metallicity increases with time
for all of the fields. We do not observe any radial gradient in the
metallicity.Comment: 9 pages, 11 figures, Accepted to A&
Técnicas de levantamento e monitoração de populações de carnívoros
Diferentes técnicas vêm sendo utilizadas em levantamentos de carnívoros, e o principal fator que influencia as estimativas é a detectabilidade. Raramente todos os animais presentes em uma dada área são detectados num levantamento, e a maioria das estimativas são baseadas em contagens incompletas. Por outro lado, nem sempre se faz necessário a obtenção de estimativas de abundãncia absoluta ou de densidade absoluta, e um índice de abundância pode ser o suficiente para, por exemplo, avaliar as tendências da população. Índices de abundância precisam ter uma forte correlação com a abundância absoluta ou com a densidade, para que sejam úteis. Índices podem ser obtidos de contagens incompletas, em relação ao esforço empregado, usando sinais da presença de animais, fotografia remota e outras técnicas. Métodos para estimar a densidade ou abundância absoluta podem ser divididos em diretas e indiretas.bitstream/CPAP/55978/1/DOC73.pdfFormato Eletrônic
Sol-Gel Synthesis and Antibacterial Characterization of Bioactive Ferrous Citrate-Silica Hybrid Materials
The aim of this work is the synthesis of therapeutic systems, iron (II) based, by sol-gel method. In a SiO2 matrix, different weight percentages of ferrous citrate (Fe(II)C are embedded. Fourier Transform Infrared (FTIR) spectroscopy is used to study the interactions among different components in the hybrid materials. The bioactivity of the synthesized hybrid materials is evaluated by the formation of a layer of hydroxyapatite on the surface of samples soaked in SBF using FTIR spectroscopy. Finally, also, the potential antibacterial properties of the different materials against two different bacteria, Staphylococcus epidermidis and Pseudomonas aeruginosa, are investigated
Dystonia: sparse synapses for D2 receptors in striatum of a DYT1 knock-out mouse model
Dystonia pathophysiology has been partly linked to downregulation and dysfunction of dopamine D2 receptors in striatum. We aimed to investigate the possible morpho-structural correlates of D2 receptor downregulation in the striatum of a DYT1 Tor1a mouse model. Adult control Tor1a+/+ and mutant Tor1a+/− mice were used. The brains were perfused and free-floating sections of basal ganglia were incubated with polyclonal anti-D2 antibody, followed by secondary immune-fluorescent antibody. Confocal microscopy was used to detect immune-fluorescent signals. The same primary antibody was used to evaluate D2 receptor expression by western blot. The D2 receptor immune-fluorescence appeared circumscribed in small disks (~0.3–0.5 μm diameter), likely representing D2 synapse aggregates, densely distributed in the striatum of Tor1a+/+ mice. In the Tor1a+/− mice the D2 aggregates were significantly smaller (μm2 2.4 ± SE 0.16, compared to μm2 6.73 ± SE 3.41 in Tor1a+/+) and sparse, with ~30% less number per microscopic field, value correspondent to the amount of reduced D2 expression in western blotting analysis. In DYT1 mutant mice the sparse and small D2 synapses in the striatum may be insufficient to “gate” the amount of presynaptic dopamine release diffusing in peri-synaptic space, and this consequently may result in a timing and spatially larger nonselective sphere of influence of dopamine action
- …