SWEET-Cat updated Sousa, S. G.; Adibekyan, V.; Delgado-Mena, E. ...
Astronomy & astrophysics,
12/2018, Letnik:
620
Journal Article
Recenzirano
Odprti dostop
Context. Exoplanets have now been proven to be very common. The number of its detections continues to grow following the development of better instruments and missions. One key step for the ...understanding of these worlds is their characterization, which mostly depend on their host stars. Aims. We perform a significant update of the Stars With ExoplanETs CATalog (SWEET-Cat), a unique compilation of precise stellar parameters for planet-host stars provided for the exoplanet community. Methods. We made use of high-resolution spectra for planet-host stars, either observed by our team or found in several public archives. The new spectroscopic parameters were derived for the spectra following the same homogeneous process (ARES+MOOG). The host star parameters were then merged together with the planet properties listed in exoplanet.eu to perform simple data analysis. Results. We present new spectroscopic homogeneous parameters for 106 planet-host stars. Sixty-three planet hosts are also reviewed with new parameters. We also show that there is a good agreement between stellar parameters derived for the same star but using spectra obtained from different spectrographs. The planet-metallicity correlation is reviewed showing that the metallicity distribution of stars hosting low-mass planets (below 30 M⊕) is indistinguishable from that from the solar neighborhood sample in terms of metallicity distribution.
Context.On October 24, 2007 the periodic comet 17P/Holmes underwent an astonishing outburst that increased its apparent total brightness from magnitude V~17 up to V~2.5 in roughly two days. In this ...contribution we report on Wendelstein 0.8 m telescope (WST) photometric observations of the early evolution stages of the outburst. Aims.We studied the evolution of the structure morphology and its kinematic and provide an estimate of the ejected dust mass. Methods.We analyzed 126 images of the comet in the BVRI photometric bands spread between October 26, 2007 and November 20, 2007. The bright comet core appeared to be separated from a quickly expanding dust cloud in all the data, and the bulk of the cloud was contained in the field of view of our instrument during the days soon after the outburst, allowing precise estimates both of the separation velocities of the two luminous baricenters and of the expansion velocity of the dust cloud. The ejected dust mass was derived on the basis of differential photometry on background stars occulted by the moving cloud. Results.The two cores were moving apart from each other at a relative, projected constant velocity of (9.87±0.07) arcsec/day (0.135±0.001 km s-1). In the inner regions of the dust cloud we observed a linear increase in size at a mean constant velocity of (14.6±0.3) arcsec/day (0.200±0.004 km s-1). Evidence of a radial velocity gradient in the expanding cloud was also found. Our estimate for the expanding coma's mass was approximately 10$^{-2}{-}1$ comet's mass, implying a significant disintegration event. Conclusions.We interpret our observations in the context of an explosive scenario that was more probably triggered by some internal instability processes rather than by an impact with an asteroidal body. Due to the peculiar characteristics of this event, further observations and investigations are necessary to bring the nature of the physical processes that determined it to light.
Gastropleural fistula represents a rare clinical event often resulting in an iatrogenic complication of gastrointestinal surgery. Clinical presentation is insidious, patients complain of chronic and ...non-specific respiratory symptoms and may be conservatively treated for lung infections for several months until detailed tests finally reveal the correct diagnosis.
We describe a case of a healthy patient with an unexpected diagnosis of empyema due to a gastropleural fistula.
A 51-year-old man with a past history of splenectomy for cyst was admitted because of high fever and cough. A chest radiography and CT-scan revealed a left-side pneumonia complicated with pleural empyema. Broad spectrum empirical antibiotics and pleural drainage did not significantly improve the clinical picture. While the need for a surgical complex thoracic approach becomes a collective awareness, questions about causes of empyema and its unfavorable evolution in our patient did not initially find a common satisfactory answer. It was only by the identification of probiotics bacteria in the pleural fluid that a gastropleural fistula was suspected, and then, it was confirmed by CT-scan and by digestive endoscopy. A combined thoraco-abdominal surgical treatment was therefore scheduled, leading to progressive improvement till total healing.
Although gastropleural fistula is rare, it is necessary to include this pathological condition in the differential diagnosis of a persistent complicated pneumonia, because early diagnosis and, consequently, surgical management, may significantly impact on the prognosis of these patients. In our case, the detection of probiotics bacteria in the pleural fluid helped us to suspect and to look for the fistula.
ABSTRACT We report on novel observations of HAT-P-1 aimed at constraining the optical transmission spectrum of the atmosphere of its transiting hot-Jupiter exoplanet. Ground-based differential ...spectrophotometry was performed over two transit windows using the DOLORES spectrograph at the Telescopio Nazionale Galileo. Our measurements imply an average planet to star radius ratio equal to Rp/R* = (0.1159 0.0005). This result is consistent with the value obtained from recent near-infrared measurements of this object, but differs from previously reported optical measurements, being lower by around 4.4 exoplanet scale heights. Analyzing the data over five different spectral bins of ∼600 wide, we observed a single peaked spectrum (3.7 level) with a blue cutoff corresponding to the blue edge of the broad absorption wing of sodium and an increased absorption in the region in-between 6180 and 7400 . We also infer that the width of the broad absorption wings due to alkali metals is likely narrower than the one implied by solar abundance clear atmospheric models. We interpret the result as evidence that HAT-P-1b has a partially clear atmosphere at optical wavelengths with a more modest contribution from an optical absorber than previously reported.
Fecal calprotectin (FC) has been proposed as a useful and non-invasive marker of acute intestinal inflammation.
We summarize recent evidences on FC, providing practical perspectives on its diagnostic ...and prognostic role in different gastrointestinal conditions.
We performed a MEDLINE search for all articles published on FC in human gastroenterology field up to December 2011. We chose evidences from well-designed and controlled studies when available. A meta-analysis was not performed because of the heterogeneity of these studies.
Most of relevant data derived from studies on inflammatory bowel disease (IBD). FC concentrations (FCCs) showed a good diagnostic precision for separating organic and functional intestinal diseases and well correlated with IBD activity. FCCs were higher in subjects with NSAID enteropathy, but the actual correlation between FC and endoscopy is under investigation. FCCs can not be recommended for colorectal neoplasia population screening purpose. Few and heterogeneous studies have been performed in order to evaluate role of FC in other gastrointestinal conditions.
FC has been widely proposed as a filter to avoid unnecessary endoscopies. Nevertheless, it should not be considered as a marker of organic intestinal disease at all; rather it represents a marker of "neutrophilic intestinal inflammation". In IBD, more and larger studies are needed to confirm FC's capacity to correlate with IBD extent, to predict response to therapy and relapse, and the presence of a subclinical intestinal inflammation in asymptomatic first-degree relatives of patients. For NSAID enteropathy, the actual correlation between FC and endoscopic results needs further confirmation. Finally, as regarding other gastrointestinal conditions, available data are still insufficient to draw any final conclusion and further studies should be encouraged.
Summary
Background Despite the reported tolerance to a low dose of lactose, many lactose malabsorbers follow a rigorous lactose‐free diet also avoiding lactose‐containing drugs. Up to now, only a few ...case reports have described the onset of gastrointestinal symptoms in lactose malabsorbers following the ingestion of these drugs. It has been suggested that capsules/tablets contain no more than 400 mg of lactose.
Aim To evaluate breath H2 excretion and intolerance symptoms after ingestion of a capsule containing 400 mg of lactose or placebo through a randomized, cross‐over, double‐blind, controlled study.
Methods Seventy‐seven lactose maldigesters with intolerance underwent two H2 breath tests with both 400 mg of lactose and 400 mg of placebo. Gastrointestinal symptoms occurring in the 8 h following the ingestion of different substrates were evaluated by a visual‐analogue scale.
Results Ingestion of 400 mg of lactose did not cause a significant difference in breath H2 excretion or in the severity of gastrointestinal symptoms compared to placebo.
Conclusion In patients with lactase deficiency, drugs containing 400 mg of lactose or less can be used safely.
ABSTRACT
The transit timing variation (TTV) method allows the detection of non‐transiting planets through their gravitational perturbations. Since TTVs are strongly enhanced in systems close to ...mean‐motion resonances (MMRs), even a low‐mass planet can produce an observable signal. This technique has thus been proposed to detect terrestrial planets. In this Letter, we analyse TTV signals for systems in or close to MMR in order to illustrate the difficulties arising in the determination of planetary parameters. TTVs are computed numerically with an N‐body integrator for a variety of systems close to MMR. The main features of these TTVs are also derived analytically. Systems deeply inside of the MMR do not produce particularly strong TTVs, while those close to MMR generate quasi‐periodic TTVs characterized by a dominant long‐period term and a low‐amplitude remainder. If the remainder is too weak to be detected, then the signal is strongly degenerate and this prevents the determination of the planetary parameters. Even though an Earth‐mass planet can be detected by the TTV method if it is close to an MMR, it may not be possible to assert that this planet is actually an Earth‐mass planet. On the other hand, if the system is right in the centre of an MMR, the high‐amplitude oscillation of the TTV signal vanishes and the detection of the perturber becomes as difficult as it is far from the MMR.
Properties of M31 Montalto, M.; Seitz, S.; Riffeser, A. ...
Astronomy & astrophysics,
09/2009, Letnik:
507, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Aims. Observations acquired by the Spitzer Space Telescope and improvements to theoretical modeling of dust emission properties are used to discuss the distribution of dust and its characteristics in ...the closest neighbor spiral galaxy M31. These data are then used with GALEX FUV, NUV, and SDSS images to study the age dependence of the dust heating process. Methods. Spitzer IRAC/MIPS maps of M31 were matched together and compared to dust emission models allowing us to constrain the dust mass, the intensity of the mean radiation field, the abundance of polycyclic aromatic hydrocarbon (PAH) particles. The total infrared emission (TIR) was analyzed as a function of UV and optical colors and compared to predictions of models that consider age-dependent dust heating. Results. We demonstrate that cold-dust component emission dominates the infrared spectral energy distribution of M31. The mean intensity of the radiation field heating the dust is low (typically $U < 2$, where $U = 1$ is the value in the solar neighborhood). Because of a lack of submillimeter observations, the dust mass $(M_{\rm dust})$ is only weakly constrained by the infrared spectrum, but we derived a lower limit of Mdust ≳ 1.1 $\times$ 107 $M_{\odot}$ with a best-fit model value of Mdust = 7.6 $\times$ 107 $M_{\odot}$, in good agreement with expectations from CO and HI measurements. Across the spiral-ring structure of M31, we show that a fraction >3% of the total dust mass is in PAHs. UV and optical colors are correlated with the total infrared to far ultraviolet (TIR/FUV) ratios in ~670 pc-sized regions over the disk of M31, although deviating from the relationship between infrared excess and ultraviolet spectral slope (referred as IRX-β relationship) for starburst galaxies. In particular, redder regions have lower values of the TIR/FUV ratio for a fixed color. Considering the predictions of models that account for the dust-heating age dependence, we found that in 83% of the regions analyzed across the 10 kpc ring, more than 50% of the energy absorbed by the dust is rediated at λ > 4000 Å and that dust in M31 appears mainly heated by populations a few Gyr old even across the star-forming ring. We also found that the attenuation varies radially peaking close to 10 kpc and decreases more rapidly with radius in the inner regions of M31 than in the outer regions in agreement with previous studies. We finally derived the attenuation map of M31 at 6″/px resolution (~100 pc/px along the plane of M31).
This review discusses one of the most relevant problems in gastrointestinal clinical practice: lactose intolerance. The role of lactase-persistence alleles the diagnosis of lactose malabsorption the ...development of lactose intolerance symptoms and its management. Most people are born with the ability to digest lactose, the major carbohydrate in milk and the main source of nutrition until weaning. Approximately, 75% of the world's population loses this ability at some point, while others can digest lactose into adulthood. Symptoms of lactose intolerance include abdominal pain, bloating, flatulence and diarrhea with a considerable intraindividual and interindividual variability in the severity. Diagnosis is most commonly performed by the non invasive lactose hydrogen breath test. Management of lactose intolerance consists of two possible clinical choice not mutually exclusive: alimentary restriction and drug therapy.
Both Centaurs and trans-Neptunian objects (TNOs) are minor bodies found in the outer Solar System. Centaurs are a transient population that moves between the orbits of Jupiter and Neptune, and they ...probably diffused out of the TNOs. TNOs move mainly beyond Neptune. Some of these objects display episodic cometary behaviour; a few percent of them are known to host binary companions. Here, we study the light-curves of two Centaurs—2060 Chiron (1977 UB) and 10199 Chariklo (1997 CU
26
)—and three TNOs—38628 Huya (2000 EB
173
), 28978 Ixion (2001 KX
76
), and 90482 Orcus (2004 DW)—and the colours of the Centaurs and Huya. Precise,
∼
1
%
,
R
-band absolute CCD photometry of these minor bodies acquired between 2006 and 2011 is presented; the new data are used to investigate the rotation rate of these objects. The colours of the Centaurs and Huya are determined using
BVRI
photometry. The point spread function of the five minor bodies is analysed, searching for signs of a coma or close companions. Astrometry is also discussed. A periodogram analysis of the light-curves of these objects gives the following rotational periods:
5.5
±
0.4
h
for Chiron,
7.0
±
0.6
h
for Chariklo,
4.45
±
0.07
h
for Huya,
12.4
±
0.3
h
for Ixion, and
11.9
±
0.5
h
for Orcus. The colour indices of Chiron are found to be
B
−
V
=
0.53
±
0.05
,
V
−
R
=
0.37
±
0.08
, and
R
−
I
=
0.36
±
0.15
. The values computed for Chariklo are
V
−
R
=
0.62
±
0.07
and
R
−
I
=
0.61
±
0.07
. For Huya, we find
V
−
R
=
0.58
±
0.09
and
R
−
I
=
0.64
±
0.20
. Our rotation periods are similar to and our colour values are consistent with those already published for these objects. We find very low levels of cometary activity (if any) and no sign of close or wide binary companions for these minor bodies.
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