By taking advantage of the superb measurements of position and velocity for an unprecedented large number of stars provided in Gaia DR2, we have generated the first maps of the rotation velocity, V rot , and vertical velocity, V z , distributions as a function of the Galactocentric radius, R gal , across a radial range of 5 < R gal < 12 kpc. In the R − V rot map, we have identified many diagonal ridge features, which are compared with the location of the spiral arms and the expected outer Lindblad resonance of the Galactic bar. We have detected also radial wave-like oscillations of the peak of the vertical velocity distribution.
Investigations of the origin and evolution of the Milky Way disk have long relied on chemical and kinematic identification of its components to reconstruct our Galactic past. Difficulties in determining precise stellar ages have restricted most studies to small samples, normally confined to the solar neighbourhood. Here we break this impasse with the help of asteroseismic inference and perform a chronology of the evolution of the disk throughout the age of the Galaxy. We chemically dissect the Milky Way disk population using a sample of red giant stars spanning out to 2 kpc in the solar annulus observed by the Kepler satellite, with the added dimension of asteroseismic ages. Our results reveal a clear difference in age between the low-and high-α populations, which also show distinct velocity dispersions in the V and W components. We find no tight correlation between age and metallicity nor [α/Fe] for the high-α disk stars. Our results indicate that this component formed over a period of more than 2 Gyr with a wide range of [M/H] and [α/Fe] independent of time. Our findings show that the kinematic properties of young α-rich stars are consistent with the rest of the high-α population and different from the low-α stars of similar age, rendering support to their origin being old stars that went through a mass transfer or stellar merger event, making them appear younger, instead of migration of truly young stars formed close to the Galactic bar.
Fermi-LAT unidentified sources (unIDs) have proven to be compelling targets for performing indirect dark matter (DM) searches. In a previous work, we found that among the 1235 unIDs in Fermi-LAT's catalogs (3FGL, 2FHL and 3FHL) only 44 of those are DM subhalos candidates. We now implement a spectral analysis to test whether these remaining sources are compatible or not with DM origin. This analysis is executed using almost 10 years of Pass 8 Fermi-LAT data. None of the unIDs are found to significantly prefer DMinduced emission compared to other, more conventional, astrophysical sources. In order to discriminate between pulsar and DM sources, we developed a new method which is based on the source's spectral curvature, peak energy, and its detection significance. We also look for spatial extension, which may be a hint for a DM origin according to our N-body simulation studies of the subhalo population. In addition, we used Gaia DR2 data to search for a potential stellar counterpart to our best DM subhalo candidates and, although no firm associations could be found, one of them coincides with the Sagittarius stream. Finally, previous constraints on the DM annihilation cross section are updated with the new number of remaining DM subhalo candidates among unIDs. Our limits now rule out canonical thermal WIMPs up to masses of 10 GeV for bb and 20 GeV for τ + τ − annihilation channels, in this way being as sensitive and complementary to those obtained from other targets and probes.
Since the advent of Gaia astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, Gaia-Sausage-Enceladus (GSE), appears to be an early “building block” given its virial mass >1010 M⊙ at infall (z ∼ 1 − 3). In order to separate the progenitor population from the background stars, we investigate its chemical properties with up to 30 element abundances from the GALAH+ Survey Data Release 3 (DR3). To inform our choice of elements for purely chemically selecting accreted stars, we analyse 4164 stars with low-α abundances and halo kinematics. These are most different to the Milky Way stars for abundances of Mg, Si, Na, Al, Mn, Fe, Ni, and Cu. Based on the significance of abundance differences and detection rates, we apply Gaussian mixture models to various element abundance combinations. We find the most populated and least contaminated component, which we confirm to represent GSE, contains 1049 stars selected via [Na/Fe] vs. [Mg/Mn] in GALAH+ DR3. We provide tables of our selections and report the chrono-chemodynamical properties (age, chemistry, and dynamics). Through a previously reported clean dynamical selection of GSE stars, including $30 < \sqrt{J_R / \, \mathrm{kpc\, km\, s^{-1}}} < 55$, we can characterise an unprecedented 24 abundances of this structure with GALAH+ DR3. With our chemical selection we characterise the dynamical properties of the GSE, for example mean $\sqrt{J_R / \, \mathrm{kpc\, km\, s^{-1}}} = 26^{+9}_ {-14}$. We find only $(29\pm 1)\%$ of the GSE stars within the clean dynamical selection region. Our methodology will improve future studies of accreted structures and their importance for the formation of the Milky Way.
Ultrasound (US) is an ideal diagnostic tool for paediatric patients owning to its high spatial and temporal resolution, real-time imaging, and lack of ionizing radiation and bedside availability. The lack of superficial adipose tissue and favorable acoustic windows in children makes US the first line of investigation for the evaluation of pleural and chest wall abnormali-ties. Lung parenchyma was previously thought to be inaccessible to ultrasound due to the presence of the air and bony thorax. The change in attitude and growing awareness of the diagnostic possibilities has led to lung ultrasound (LUS) being accepted as a valuable point of care method. In addition, the application of LUS has widened with improvements in technology such as higher resolution transducers, harmonic imaging and contrast-enhanced ultrasound. In the current World Federation of Societies for Ultrasound in Medicine and Biology (WFUMB) paper series the topic will be introduced, the technical requirements explained and the use of ultrasound in the lung and pleura in pediatric patients are discussed.
The aim of this review was to describe the current knowledge about coronavirus disease 2019 (COVID-19, which is caused by severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) in children, from epidemiological, clinical, and laboratory perspectives, including knowledge on the disease course, treatment, and prognosis. An extensive literature search was performed to identify papers on COVID-19 (SARS-CoV-2 infection) in children, published between January 1, 2020 and April 1, 2020. There were 44 relevant papers on COVID-19 in children. The results showed that COVID-19 occurs in 0.39-12.3% of children. Clinical signs and symptoms are comparable to those in adults, but milder forms and a large percentage of asymptomatic carriers are found among children. Elevated inflammatory markers are associated with complications and linked to various co-infections. Chest computed tomography (CT) scans in children revealed structural changes similar to those found in adults, with consolidations surrounded by halos being somewhat specific for children with COVID-19. The recommended treatment includes providing symptomatic therapy, with no specific drug recommendations for children. The prognosis is much better for children compared to adults. This review highlights that COVID-19 in children is similar to the disease in the adult population, but with particularities regarding clinical manifestations, laboratory test results, chest imaging, and treatment. The prognosis is much better for children compared to adults, but with the progression of the pandemic; the cases in children might change in the future.
Ultrasound (US) is an ideal diagnostic tool for paediatric patients owning to its high spatial and temporal resolution, real-time imaging, and lack of ionizing radiation and bedside availability. In the current World Federation of Societies for Ultra-sound in Medicine and Biology (WFUMB) paper series so far (part I) the topic has been introduced and the technical require-ments explained. In the present paper the use of US in the lung in paediatric patients is analysed. Lung diseases including the interstitial syndrome, bacterial pneumonia and viral infections, CoViD findings, atelectasis, lung consolidation, bronchiolitis and congenital diseases of the respiratory system including congenital pulmonary airway malformation (CPAM) and sequester but also pneumothorax are discussed.
Several diagnostic methods for the evaluation and monitoring were used to find out the pro-inflammatory status, as well as incidence of sepsis in critically ill patients. One such recent method is based on investigating the genetic polymorphisms and determining the molecular and genetic links between them, as well as other sepsis-associated pathophysiologies. Identification of genetic polymorphisms in critical patients with sepsis can become a revolutionary method for evaluating and monitoring these patients. Similarly, the complications, as well as the high costs associated with the management of patients with sepsis, can be significantly reduced by early initiation of intensive care.
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