Finding new molecular pathways and strategies modulating lipolysis in adipocytes is an attractive goal of the current research. Indeed, it is becoming clear that several human age-related pathologies ...are caused by adipose tissue expansion and altered lipid metabolism. In the present work, we show that transcription factor forkhead homeobox type protein O1 (FoxO1) is upregulated by nutrient restriction (NR) in adipocytes and exerts the transcriptional control of lipid catabolism via the induction of lysosomal acid lipase (Lipa). An increased autophagy and colocalization of lipid droplets (LDs) with lysosomes was observed implying lipophagy in Lipa-mediated LDs degradation. Interestingly, we found that metformin (Metf), a biguanide drug commonly used to treat type-2 diabetes, exerts effects comparable to that of NR. Actually, it was able to elicit FoxO1-dependent Lipa induction as well as LDs degradation through lipophagy. Moreover, we demonstrate that, during NR or Metf treatment, free fatty acids released by Lipa are directed toward AMP-activated protein kinase-mediated mitochondrial oxidation, thus maintaining energetic homeostasis in adipocytes. In conclusion, our data show that lysosomal-mediated lipid catabolism is activated by NR in adipocytes and give further support to the use of Metf as a NR mimetic to combat age-related diseases associated with altered lipid metabolism.
The nutrient-sensing lipolytic enzyme adipose triglyceride lipase (ATGL) has a key role in adipose tissue function, and alterations in its activity have been implicated in many age-related metabolic ...disorders. In adipose tissue reduced blood vessel density is related to hypoxia state, cell death and inflammation. Here we demonstrate that adipocytes of poorly vascularized enlarged visceral adipose tissue (i.e. adipose tissue of old mice) suffer from limited nutrient delivery. In particular, nutrient starvation elicits increased activity of mitochondrial proline oxidase/dehydrogenase (POX/PRODH) that is causal in triggering a ROS-dependent induction of ATGL. We demonstrate that ATGL promotes the expression of genes related to mitochondrial oxidative metabolism (peroxisome proliferator-activated receptor-α, peroxisome proliferator-activated receptor-γ coactivator-1α), thus setting a metabolic switch towards fat utilization that supplies energy to starved adipocytes and prevents cell death, as well as adipose tissue inflammation. Taken together, these results identify ATGL as a stress resistance mediator in adipocytes, restraining visceral adipose tissue dysfunction typical of age-related metabolic disorders.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Context. The assessment of the frequency of planetary systems reproducing the solar system’s architecture is still an open problem in exoplanetary science. Detailed study of multiplicity and ...architecture is generally hampered by limitations in quality, temporal extension and observing strategy, causing difficulties in detecting low-mass inner planets in the presence of outer giant planets. Aims. We present the results of high-cadence and high-precision HARPS observations on 20 solar-type stars known to host a single long-period giant planet in order to search for additional inner companions and estimate the occurence rate fp of scaled solar system analogues – in other words, systems featuring lower-mass inner planets in the presence of long-period giant planets. Methods. We carried out combined fits of our HARPS data with literature radial velocities using differential evolution MCMC to refine the literature orbital solutions and search for additional inner planets. We then derived the survey detection limits to provide preliminary estimates of fp. Results. We generally find better constrained orbital parameters for the known planets than those found in the literature; significant updates can be especially appreciated on half of the selected planetary systems. While no additional inner planet is detected, we find evidence for previously unreported long-period massive companions in systems HD 50499 and HD 73267. We finally estimate the frequency of inner low mass (10–30 M⊕) planets in the presence of outer giant planets as fp < 9.84% for P < 150 days. Conclusions. Our preliminary estimate of fp is significantly lower than the literature values for similarly defined mass and period ranges; the lack of inner candidate planets found in our sample can also be seen as evidence corroborating the inwards-migration formation model for super-Earths and mini-Neptunes. Our results also underline the need for high-cadence and high-precision followup observations as the key to precisely determine the occurence of solar system analogues.
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Context. High-precision photometry can lead to the detection of secondary eclipses and phase variations of highly irradiated planets. Aims. We performed a homogeneous search and analysis of optical ...occultations and phase variations of the most favorable ultra-short-period (USP) (P < 1 days) sub-Neptunes (Rp < 4 R⊕), observed by Kepler and K2, with the aim to better understand their nature. Methods. We first selected 16 Kepler and K2 USP sub-Neptunes based on the expected occultation signal. We filtered out stellar variability in the Kepler light curves, using a sliding linear fitting and, when required, a more sophisticated approach based on a Gaussian process regression. In the case of the detection of secondary eclipse or phase variation with a confidence level higher than 2σ, we simultaneously modeled the primary transit, secondary eclipse, and phase variations in a Bayesian framework, by using information from previous studies and knowledge of the Gaia parallaxes. We further derived constraints on the geometric albedo as a function of the planet’s brightness temperature. Results. We confirm the optical secondary eclipses for Kepler-10b (13σ), Kepler-78b (9.5σ), and K2-141b (6.9σ), with marginal evidence for K2-312b (2.2σ). We report new detections for K2-106b (3.3σ), K2-131b (3.2σ), Kepler-407b (3.0σ), and hints for K2-229b (2.5σ). For all targets, with the exception of K2-229b and K2-312b, we also find phase curve variations with a confidence level higher than 2σ. Conclusions. Two USP planets, namely Kepler-10b and Kepler-78b, show non-negligible nightside emission. This questions the scenario of magma-ocean worlds with inefficient heat redistribution to the nightside for both planets. Due to the youth of the Kepler-78 system and the small planetary orbital separation, the planet may still retain a collisional secondary atmosphere capable of conducting heat from the day to the nightside. Instead, the presence of an outgassing magma ocean on the dayside and the low high-energy irradiation of the old host star may have enabled Kepler-10b to build up and retain a recently formed collisional secondary atmosphere. The magma-world scenario may instead apply to K2-141b and K2-131b.
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Context
. The formation mechanisms of stellar, brown dwarf, and planetary companions, their dependencies on the environment and their interactions with each other are still not well established. ...Recently, combining high-contrast imaging and space astrometry we found that Jupiter-like (JL) planets are frequent in the
β
Pic moving group (BPMG) around those stars where their orbit can be stable, prompting further analysis and discussion.
Aims
. We broaden our previous analysis to other young nearby associations to determine the frequency, mass and separation of companions in general and JL in particular and their dependencies on the mass and age of the associations.
Methods
. We collected available data about companions to the stars in the BPMG and seven additional young associations, including those revealed by visual observations, eclipses, spectroscopy and astrometry.
Results
. We determined search completeness and found that it is very high for stellar companions, while completeness corrections are still large for JL companions. Once these corrections are included, we found a high frequency of companions, both stellar (>0.52 ± 0.03) and JL (0.57 ± 0.11). The two populations are clearly separated by a gap that corresponds to the well-known brown dwarf desert. Within the population of massive companions, we found clear trends in frequency, separation, and mass ratios with stellar mass. Planetary companions pile up in the region just outside the ice line and we found them to be frequent once completeness was considered. The frequency of JL planets decreases with the overall mass and possibly the age of the association.
Conclusions
. We tentatively identify the two populations as due to disk fragmentation and core accretion, respectively. The distributions of stellar companions with a semi-major axis <1000 au is indeed well reproduced by a simple model of formation by disk fragmentation. The observed trends with stellar mass can be explained by a shorter but much more intense phase of accretion onto the disk of massive stars and by a more steady and prolonged accretion on solar-type stars. Possible explanations for the trends in the population of JL planets with association mass and age are briefly discussed.
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Cultural competence is a valuable and intangible heritage of knowledge, relationships and identity. Cultural competence is fundamental in nursing: sharing the objectives of all patients - not only ...foreigners - promotes patient's participation in healthcare and supports nurses' professional development, enhancing the intellectual capital that guides quality care. The aim of this study is to evaluate nurses' self-perceived cultural competence.
This is a cross-sectional study.
A self-administered cultural-competence questionnaire was used. Nurses working in hospitals and territorial healthcare settings in Rome, Italy, were involved in this study, from March 2017 to February 2018.
This study involved 192 nurses. The mean age was 46.2 ± 7.9. Most of the nurses (77.6%) were women. The nurses' mean work experience was 21.4 ± 8.8 years; 65.1% of them had never attended any type of course concerning multiculturalism. The mean score of the nurses' cultural competence was 4.19 ± 0.57 (range = 2.75-5.71). In all, 41.7% of the nurses did not consider themselves neither competent nor incompetent.
The results show that nurses have an acceptable level of cultural competence, slightly higher in the territorial context.
ABSTRACT
We present broad-band photometry of 30 planetary transits of the ultra-hot-Jupiter KELT-16 b, using five medium-class telescopes. The transits were monitored through standard $B,\, V,\, R,\, ...I$ filters and four were simultaneously observed from different places, for a total of 36 new light curves. We used these new photometric data and those from the TESS space telescope to review the main physical properties of the KELT-16 planetary system. Our results agree with previous measurements but are more precise. We estimated the mid-transit times for each of these transits and combined them with others from the literature to obtain 69 epochs, with a time baseline extending over more than 4 yr, and searched for transit time variations. We found no evidence for a period change, suggesting a lower limit for orbital decay at 8 Myr, with a lower limit on the reduced tidal quality factor of $Q^{\prime }_{\star }\gt (1.9 \pm 0.8) \times 10^5$ with $95{{\rm {per\ cent}}}$ confidence. We built up an observational, low-resolution transmission spectrum of the planet, finding evidence of the presence of optical absorbers, although with a low significance. Using TESS data, we reconstructed the phase curve finding that KELT-16 b has a phase offset of 25.25 ± 14.03 °E, a day- and night-side brightness temperature of 3190 ± 61 K and 2668 ± 56 K, respectively. Finally, we compared the flux ratio of the planet over its star at the TESS and Spitzer wavelengths with theoretical emission spectra, finding evidence of a temperature inversion in the planet’s atmosphere, the chemical composition of which is preferably oxygen-rich rather than carbon-rich.
ABSTRACT
We present rotation period measurements for 107 M dwarfs in the mass range $0.15\!-\!0.70 \, \mathrm{M}_\odot$ observed within the context of the APACHE photometric survey. We measure ...rotation periods in the range 0.5–190 d, with the distribution peaking at ∼30 d. We revise the stellar masses and radii for our sample of rotators by exploiting the Gaia DR2 data. For ${\sim}20{{\ \rm per\ cent}}$ of the sample, we compare the photometric rotation periods with those derived from different spectroscopic indicators, finding good correspondence in most cases. We compare our rotation periods distribution to the one obtained by the Kepler survey in the same mass range, and to that derived by the MEarth survey for stars in the mass range $0.07\!-\!0.25 \, \mathrm{M}_\odot$. The APACHE and Kepler periods distributions are in good agreement, confirming the reliability of our results, while the APACHE distribution is consistent with the MEarth result only for the older/slow rotators, and in the overlapping mass range of the two surveys. Combining the APACHE/Kepler distribution with the MEarth distribution, we highlight that the rotation period increases with decreasing stellar mass, in agreement with previous work. Our findings also suggest that the spin-down time scale, from fast to slow rotators, changes crossing the fully convective limit at ${\approx}0.3 \, \mathrm{M}_\odot$ for M dwarfs. The catalogue of 107 rotating M dwarfs presented here is particularly timely, as the stars are prime targets for the potential identification of transiting small planets with TESS and amenable to high-precision mass determination and further atmospheric characterization measurements.
Context.
Circumstellar debris disks provide insight into the formation and early evolution of planetary systems. Resolved belts in particular help to locate planetesimals in exosystems, and can hint ...at the presence of disk-sculpting exoplanets.
Aims.
We study the circumstellar environment of HD 112810 (HIP 63439), a mid-F-type star in the Sco-Cen association with a significant infrared excess indicating the presence of a circumstellar debris disk.
Methods.
We collected five high-contrast observations of HD 112810 with VLT/SPHERE. We identified a debris disk in scattered light, and found that the debris signature is robust over a number of epochs and a variety of reduction techniques. We modeled the disk, accounting for self-subtraction and assuming that it is optically thin.
Results.
We find a single-belt debris disk, with a radius of 118 ± 9 au and an inclination angle of 75.7
−1.3
+1.1
. This is in good agreement with the constraints from spectral energy distribution modeling and from a partially resolved ALMA image of the system. No planets are detected, though planets below the detection limit (~2.6
M
J
at a projected separation of 118 au) could be present and could have contributed to sculpting the ring of debris.
Conclusions.
HD 112810 adds to the growing inventory of debris disks imaged in scattered light. The disk is faint, but the radius and the inclination of the disk are promising for follow-up studies of the dust properties.
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