15,892 research outputs found

    Symmetry breaking results for problems with exponential growth in the unit disk

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    We investigate some asymptotic properties of extrema to a two-dimensional variational problem in the unit disk. Some results about non-radialicity of solutions are given.Comment: 17 page

    Perinatal and newborn care in a two years retrospective study in a first level peripheral hospital in Sicily (Italy)

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    BACKGROUND: Two hundred seventy-five thousand maternal deaths, 2.7 million neonatal deaths, and 2.6 million stillbirths have been estimated in 2015 worldwide, almost all in low-income countries (LICs). Moreover, more than 20 million severe disabilities result from the complications of pregnancy, childbirth or its management each year. A significant decrease of mortality/morbidity rates could be achieved by providing effective perinatal and newborn care also in high-income countries (HICs), especially in peripheral hospitals and/or rural areas, where the number of childbirths per year is often under the minimal threshold recognized by the reference legislation. We report on a 2 years retrospective cohort study, conducted in a first level peripheral hospital in Cefalù, a small city in Sicily (Italy), to evaluate care provided and mortality/morbidity rates. The proposed goal is to improve the quality of care, and the services that peripheral centers can offer. METHODS: We collected data from maternity and neonatal records, over a 2-year period from January 2017 to December 2018. The informations analyzed were related to demographic features (age, ethnicity/origin area, residence, educational level, marital status), diagnosis at admission (attendance of birth training courses, parity, type of pregnancy, gestational age, fetal presentation), mode of delivery, obstetric complications, the weight of the newborns, their feeding and eventual transfer to II level hospitals, also through the Neonatal Emergency Transport Service, if the established criteria were present. RESULTS: Eight hundred sixteen women were included (age 18-48 years). 179 (22%) attended birth training courses. 763 (93%) were Italian, 53 foreign (7%). 175 (21%) came from outside the province of Palermo. Eight hundred ten were single pregnancies, 6 bigeminal; 783 were at term (96%), 33 preterm (4%, GA 30-41 WG); 434 vaginal deliveries (53%), 382 caesarean sections (47%). One maternal death and 28 (3%) obstetric complications occurred during the study period. The total number of children born to these women was 822, 3 of which stillbirths (3.6‰). 787 (96%) were born at term (>37WG), 35 preterm (4%), 31 of which late preterm. Twenty-one newborns (2.5%) were transferred to II level hospitals. Among them, 3 for moderate/severe prematurity, 18 for mild prematurity/other pathology. The outcome was favorable for all women (except 1 hysterectomy) and the newborns transferred, and no neonatal deaths occurred in the biennium under investigation. Of the remaining 798 newborns, 440 were breastfed at discharge (55%), 337 had a mixed feeding (breastfed/formula fed, 42%) and 21 were formula fed (3%). CONCLUSIONS: Although the minimal standard of adequate perinatal care in Italy is >500 childbirths/year, the aims of the Italian legislation concern the rationalization of birth centers as well as the structural, technological and organizational improvement of health facilities. Therefore, specific contexts and critical areas need to be identified and managed. Adequate resources and intervention strategies should be addressed not only to perinatal emergencies, but also to the management of mild prematurity/pathology, especially in vulnerable populations for social or orographic reasons. The increasing availability and spread of health care offers, even in HICs, cannot be separated from the goal of quality of care, which is an ethic and public health imperative

    On the evolution of the molecular line profiles induced by the propagation of C-shock waves

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    We present the first results of the expected variations of the molecular line emission arising from material recently affected by C-shocks (shock precursors). Our parametric model of the structure of C-shocks has been coupled with a radiative transfer code to calculate the molecular excitation and line profiles of shock tracers such as SiO, and of ion and neutral molecules such as H13CO+ and HN13C, as the shock propagates through the unperturbed medium. Our results show that the SiO emission arising from the early stage of the magnetic precursor typically has very narrow line profiles slightly shifted in velocity with respect to the ambient cloud. This narrow emission is generated in the region where the bulk of the ion fluid has already slipped to larger velocities in the precursor as observed toward the young L1448-mm outflow. This strongly suggests that the detection of narrow SiO emission and of an ion enhancement in young shocks, is produced by the magnetic precursor of C-shocks. In addition, our model shows that the different velocity components observed toward this outflow can be explained by the coexistence of different shocks at different evolutionary stages, within the same beam of the single-dish observations.Comment: 7 pages, 4 figures, accepted for publication in Ap

    The magnetic precursor of L1448-mm: Excitation differences between ion and neutral fluids

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    Shock modelling predicts an electron density enhancement within the magnetic precursor of C-shocks. Previous observations of SiO, H13CO+, HN13C and H13CN toward the young L1448-mm outflow showed an over-excitation of the ion fluid that was attributed to an electron density enhancement in the precursor. We re-visit this interpretation and test if it still holds when we consider different source morphologies and kinetic temperatures for the observed molecules, and also give some insight on the spatial extent of the electron density enhancement around L1448-mm. We estimate the opacities of H13CO+ and HN13C by observing the J=3\to2 lines of rarer isotopologues to confirm that the emission is optically thin. To model the excitation of the molecules, we use the large velocity gradient (LVG) approximation with updated collisional coefficients to i) re- analyse the observations toward the positions where the over-excitation of H13CO+ has previously been observed [i.e. toward L1448- mm at offsets (0,0) and (0,-10)], and ii) to investigate if the electron density enhancement is still required for the cases of extended and compact emission, and for kinetic temperatures of up to 400 K. We also report several lines of SiO, HN13C and H13CO+ toward new positions around this outflow, to investigate the spatial extent of the over-excitation of the ions in L1448-mm. From the isotopologue observations, we find that the emission of H13CO+ and HN13C from the precursor is optically thin if this emission is extended. Using the new collisional coefficients, an electron density enhancement is still needed to explain the excitation of H13CO+ for extended emission and for gas temperatures of\le 400 K toward L1448-mm (0,-10), and possibly also toward L1448-mm (0,0). For compact emission the data cannot be fitted. We do not find any evidence for the over-excitation of the ion fluid toward the newly observed positions around L1448-mm. The observed line emission of SiO, H13CO+ and HN13C toward L1448-mm (0,0) and (0,-10) is consistent with an electron density enhancement in the precursor component, if this emission is spatially extended. This is also true for the case of high gas temperatures (\le400 K) toward the (0,-10) offset. The electron density enhancement seems to be restricted to the southern, redshifted lobe of the L1448-mm outflow. Interferometric images of the line emission of these molecules are needed to confirm the spatial extent of the over-excitation of the ions and thus, of the electron density enhancement in the magnetic precursor of L1448-mm.Comment: Accepted for publication in A&A; 9 pages, 3 figure

    Physical Properties of Galactic Planck Cold Cores revealed by the Hi-GAL survey

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    Previous studies of the initial conditions of massive star formation have mainly targeted Infrared-Dark Clouds (IRDCs) toward the inner Galaxy. This is due to the fact that IRDCs were first detected in absorption against the bright mid-IR background, requiring a favourable location to be observed. By selection, IRDCs represent only a fraction of the Galactic clouds capable of forming massive stars and star clusters. Due to their low dust temperatures, IRDCs are bright in the far-IR and millimeter and thus, observations at these wavelengths have the potential to provide a complete sample of star-forming massive clouds across the Galaxy. Our aim is to identify the clouds at the initial conditions of massive star formation across the Galaxy and compare their physical properties as a function of their Galactic location. We have examined the physical properties of a homogeneous galactic cold core sample obtained with the Planck satellite across the Galactic Plane. With the use of Herschel Hi-GAL observations, we have characterized the internal structure of them. By using background-subtracted Herschel images, we have derived the H2 column density and dust temperature maps for 48 Planck clumps. Their basic physical parameters have been calculated and analyzed as a function of location within the Galaxy. These properties have also been compared with the empirical relation for massive star formation derived by Kauffmann & Pillai (2010). Most of the Planck clumps contain signs of star formation. About 25% of them are massive enough to form high mass stars. Planck clumps toward the Galactic center region show higher peak column densities and higher average dust temperatures than those of the clumps in the outer Galaxy. Although we only have seven clumps without associated YSOs, the Hi-GAL data show no apparent differences in the properties of Planck cold clumps with and without star formation.Comment: 22 pages, 11 figures, accepted for publication in A&
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