971 research outputs found
Continuous Reasoning for Managing Next-Gen Distributed Applications.
Continuous reasoning has proven effective in incrementally analysing changes in application codebases within Continuous Integration/Continuous Deployment (CI/CD) software release pipelines. In this article, we present a novel declarative continuous reasoning approach to support the management of multi-service applications over the Cloud-IoT continuum, in particular when infrastructure variations impede meeting application's hardware, software, IoT or network QoS requirements. We show how such an approach brings considerable speed-ups compared to non-incremental reasoning
Exoplanet atmospheres with GIANO II. Detection of molecular absorption in the dayside spectrum of HD 102195b
The study of exoplanetary atmospheres is key to understand the differences
between their physical, chemical and dynamical processes. Up to now, the bulk
of atmospheric characterization analysis has been conducted on transiting
planets. On some sufficiently bright targets, high-resolution spectroscopy
(HRS) has also been successfully tested for non-transiting planets. We study
the dayside of the non-transiting planet HD 102195b using the GIANO
spectrograph mounted at TNG, demonstrating the feasibility of atmospheric
characterization measurements and molecular detection for non-transiting
planets with the HRS technique using 4-m class telescopes. The Doppler-shifted
planetary signal changes on the order of many km/s during the observations, in
contrast with the telluric absorption which is stationary in wavelength,
allowing us to remove the contamination from telluric lines while preserving
the features of the planetary spectrum. The emission signal from HD 102195b's
atmosphere is then extracted by cross-correlating the residual spectra with
atmospheric models. We detect molecular absorption from water vapor at
4.4 level. We also find convincing evidence for the presence of
methane, which is detected at the 4.1 level. The two molecules are
detected with a combined significance of 5.3, at a semi-amplitude of
the planet radial velocity km/s. We estimate a planet true mass
of and orbital inclination between 72.5 and
84.79 (1). Our analysis indicates a non-inverted atmosphere
for HD 102195b, as expected given the relatively low temperature of the planet,
inefficient to keep TiO/VO in gas phase. Moreover, a comparison with
theoretical expectations and chemical model predictions corroborates our
methane detection and suggests that the detected and signatures
could be consistent with a low C/O ratio.Comment: 12 pages, 12 figures, accepted for publication in A&
Exoplanet atmospheres with GIANO. I. Water in the transmission spectrum of HD 189733b
High-resolution spectroscopy (R 20,000) at near-infrared wavelengths
can be used to investigate the composition, structure, and circulation patterns
of exoplanet atmospheres. However, up to now it has been the exclusive dominion
of the biggest telescope facilities on the ground, due to the large amount of
photons necessary to measure a signal in high-dispersion spectra. Here we show
that spectrographs with a novel design - in particular a large spectral range -
can open exoplanet characterisation to smaller telescope facilities too. We aim
to demonstrate the concept on a series of spectra of the exoplanet HD 189733 b
taken at the Telescopio Nazionale Galileo with the near-infrared spectrograph
GIANO during two transits of the planet. In contrast to absorption in the
Earth's atmosphere (telluric absorption), the planet transmission spectrum
shifts in radial velocity during transit due to the changing orbital motion of
the planet. This allows us to remove the telluric spectrum while preserving the
signal of the exoplanet. The latter is then extracted by cross-correlating the
residual spectra with template models of the planet atmosphere computed through
line-by-line radiative transfer calculations, and containing molecular
absorption lines from water and methane. By combining the signal of many
thousands of planet molecular lines, we confirm the presence of water vapour in
the atmosphere of HD 189733 b at the 5.5- level. This signal was
measured only in the first of the two observing nights. By injecting and
retrieving artificial signals, we show that the non-detection on the second
night is likely due to an inferior quality of the data. The measured strength
of the planet transmission spectrum is fully consistent with past CRIRES
observations at the VLT, excluding a strong variability in the depth of
molecular absorption lines.Comment: 10 pages, 8 figures. Accepted for publication in Astronomy &
Astrophysics. v2 includes language editin
Protected areas as refuges for pest species? The case of wild boar
Abstract Protected areas are often blamed for offering refuge to pest species populations, giving rise to the so-called "reserve effect". Nevertheless, this major conservation side effect has seldom been investigated or verified on a local scale. Along the borders of two protected areas of different size, we modelled wild boar individual likelihood of being either inside or outside the protected areas throughout the year, considering their activity rhythms and resource availability. No evidence of reserve effect was found in the small protected area, yet the percentage of wild boar moving across the border was smaller in the large one. Moreover, although wild boar use of the large protected area resulted to increase in autumn, we showed that this was not the consequence of hunting avoidance. Our results clearly highlighted the importance to verify reserve effect on a local scale with studies based on detailed information on animal spatial behaviour and environmental variables
Identification of Sesamin from Sesamum indicum as a Potent Antifungal Agent Using an Integrated in Silico and Biological Screening Platform
Due to the limited availability of antifungal drugs, their relevant side effects and considering the insurgence of drug-resistant strains, novel antifungal agents are urgently needed. To identify such agents, we have developed an integrated computational and biological screening platform. We have considered a promising drug target in antifungal drug discovery (exo-1,3-β-glucanase) and a phytochemical library composed of bioactive natural products was used. These products were computationally screened against the selected target using molecular docking and molecular dynamics techniques along with the evaluation of drug-like profile. We selected sesamin as the most promising phytochemical endowed with a potential antifungal profile and satisfactory drug-like properties. Sesamin was submitted to a preliminary biological evaluation to test its capability to inhibit the growth of several Candida species by calculating the MIC/MFC and conducting synergistic experiments with the marketed drug fluconazole. Following the screening protocol, we identified sesamin as a potential exo-1,3-β-glucanase inhibitor, with relevant potency in inhibiting the growth of Candida species in a dose-dependent manner (MIC and MFC of 16 and 32 μg/mL, respectively). Furthermore, the combination of sesamin with fluconazole highlighted relevant synergistic effects. The described screening protocol revealed the natural product sesamin as a potential novel antifungal agent, showing an interesting predicted pharmacological profile, paving the way to the development of innovative therapeutics against fungal infections. Notably, our screening protocol can be helpful in antifungal drug discovery
Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 microns
We report a 4.8 sigma detection of water absorption features in the day side
spectrum of the hot Jupiter HD 189733 b. We used high-resolution (R~100,000)
spectra taken at 3.2 microns with CRIRES on the VLT to trace the
radial-velocity shift of the water features in the planet's day side atmosphere
during 5 h of its 2.2 d orbit as it approached secondary eclipse. Despite
considerable telluric contamination in this wavelength regime, we detect the
signal within our uncertainties at the expected combination of systemic
velocity (Vsys=-3 +5-6 km/s) and planet orbital velocity (Kp=154 +14-10 km/s),
and determine a H2O line contrast ratio of (1.3+/-0.2)x10^-3 with respect to
the stellar continuum. We find no evidence of significant absorption or
emission from other carbon-bearing molecules, such as methane, although we do
note a marginal increase in the significance of our detection to 5.1 sigma with
the inclusion of carbon dioxide in our template spectrum. This result
demonstrates that ground-based, high-resolution spectroscopy is suited to
finding not just simple molecules like CO, but also to more complex molecules
like H2O even in highly telluric contaminated regions of the Earth's
transmission spectrum. It is a powerful tool that can be used for conducting an
immediate census of the carbon- and oxygen-bearing molecules in the atmospheres
of giant planets, and will potentially allow the formation and migration
history of these planets to be constrained by the measurement of their
atmospheric C/O ratios.Comment: 5 pages, 4 figures, accepted for publication in MNRAS Letter
Dusty tails of evaporating exoplanets. II. Physical modelling of the KIC 12557548b light curve
Evaporating rocky exoplanets, such as KIC 12557548b, eject large amounts of
dust grains, which can trail the planet in a comet-like tail. When such objects
occult their host star, the resulting transit signal contains information about
the dust in the tail. We aim to use the detailed shape of the Kepler light
curve of KIC 12557548b to constrain the size and composition of the dust grains
that make up the tail, as well as the mass loss rate of the planet. Using a
self-consistent numerical model of the dust dynamics and sublimation, we
calculate the shape of the tail by following dust grains from their ejection
from the planet to their destruction due to sublimation. From this dust cloud
shape, we generate synthetic light curves (incorporating the effects of
extinction and angle-dependent scattering), which are then compared with the
phase-folded Kepler light curve. We explore the free-parameter space thoroughly
using a Markov chain Monte Carlo method. Our physics-based model is capable of
reproducing the observed light curve in detail. Good fits are found for initial
grain sizes between 0.2 and 5.6 micron and dust mass loss rates of 0.6 to 15.6
M_earth/Gyr (2-sigma ranges). We find that only certain combinations of
material parameters yield the correct tail length. These constraints are
consistent with dust made of corundum (Al2O3), but do not agree with a range of
carbonaceous, silicate, or iron compositions. Using a detailed, physically
motivated model, it is possible to constrain the composition of the dust in the
tails of evaporating rocky exoplanets. This provides a unique opportunity to
probe to interior composition of the smallest known exoplanets.Comment: 18 pages, 11 figures, A&A accepte
In Vitro and In Silico Analyses of New Cinnamid and Rosmarinic Acid-Derived Compounds Biosynthesized in Escherichia coli as Leishmania amazonensis Arginase Inhibitors
Arginase is a metalloenzyme that plays a central role in Leishmania infections. Previously, rosmarinic and caffeic acids were described as antileishmanial agents and as Leishmania amazonensis arginase inhibitors. Here, we describe the inhibition of arginase in L. amazonensis by rosmarinic acid analogs (1–7) and new caffeic acid-derived amides (8–10). Caffeic acid esters and amides were produced by means of an engineered synthesis in E. coli and tested against L. amazonensis arginase. New amides (8–10) were biosynthesized in E. coli cultured with 2 mM of different combinations of feeding substrates. The most potent arginase inhibitors showed Ki(s) ranging from 2 to 5.7 μM. Compounds 2–4 and 7 inhibited L. amazonensis arginase (L-ARG) through a noncompetitive mechanism whilst compound 9 showed a competitive inhibition. By applying an in silico protocol, we determined the binding mode of compound 9. The competitive inhibitor of L-ARG targeted the key residues within the binding site of the enzyme, establishing a metal coordination bond with the metal ions and a series of hydrophobic and polar contacts supporting its micromolar inhibition of L-ARG. These results highlight that dihydroxycinnamic-derived compounds can be used as the basis for developing new drugs using a powerful tool based on the biosynthesis of arginase inhibitors
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Distinct patterns of expression of fibroblast growth factors and their receptors in human atheroma and nonatherosclerotic arteries. Association of acidic FGF with plaque microvessels and macrophages
Because fibroblast growth factors (FGFs) modulate important functions of endothelial cells (EC) and smooth muscle cells (SMC), we studied FGF expression in human vascular cells and control or atherosclerotic arteries. All cells and arteries contained acidic (a) FGF and basic (b) FGF mRNA. Northern analysis detected aFGF mRNA only in one of five control arteries but in all five atheroma tested, while levels of bFGF mRNA did not differ among control (n = 3) vs. plaque specimens (n = 6). Immunolocalization revealed abundant bFGF protein in control vessels (n = 10), but little in plaques (n = 14). In contrast, atheroma (n = 14), but not control arteries (n = 10), consistently exhibited immunoreactive aFGF, notably in neovascularized and macrophage-rich regions of plaque. Because macrophages colocalized with aFGF, we tested human monocytoid THP-1 cells and demonstrated accumulation of aFGF mRNA during PMA-induced differentiation. We also examined the expression of mRNA encoding FGF receptors (FGFRs). All cells and arteries contained FGFR-1 mRNA. Only SMC and control vessels had FGFR-2 mRNA, while EC and some arteries contained FGFR-4 mRNA. The relative lack of bFGF in plaques vs. normal arteries suggests that this growth factor may not contribute to cell proliferation in advanced atherosclerosis. However, aFGF produced by plaque macrophages may stimulate the growth of microvessels during human atherogenesis
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