Abstract
Down syndrome (DS) is the most common genetic cause of developmental disabilities. Advanced analysis of brain magnetic resonance imaging (MRI) has been used to find brain abnormalities and ...their relationship to neurocognitive impairments in children and adolescents with DS. Because genetic factors affect brain development in early fetal life, there is a growing interest in analyzing brains from living fetuses with DS. In this study, we investigated regional sulcal folding depth as well as global cortical gyrification from fetal brain MRIs. Nine fetuses with DS (29.1 ± 4.24 gestational weeks mean ± standard deviation) were compared with 17 typically developing TD fetuses (28.4 ± 3.44). Fetuses with DS showed lower whole-brain average sulcal depths and gyrification index than TD fetuses. Significant decreases in sulcal depth were found in bilateral Sylvian fissures and right central and parieto-occipital sulci. On the other hand, significantly increased sulcal depth was shown in the left superior temporal sulcus, which is related to atypical hemispheric asymmetry of cortical folding. Moreover, these group differences increased as gestation progressed. This study demonstrates that regional sulcal depth is a sensitive marker for detecting alterations of cortical development in DS during fetal life, which may be associated with later neurocognitive impairment.
Purpose
The incidence of inguinal hernia is higher in elderly because of aging-related diseases like prostatism, bronchitis, collagen laxity. A conservative management is common in elderly to reduce ...surgery-related risks, however watchful waiting can expose to obstruction and strangulation. The aim of the present study was to assess the impact of emergency surgery in a large series of elderly with complicated groin hernia and to identify the independent risk factors for postoperative morbidity and mortality. The predictive performance of prognostic risk scores has been also assessed.
Methods
This is a prospective observational study carried out between January 2017 and June 2018 in elderly patients who underwent emergency surgery for complicated hernia in 38 Italian hospitals. Pre-operative, surgical and postoperative data were recorded for each patient. ASA score, Charlson’s comorbidity index, P-POSSUM and CR-POSSUM were assessed.
Results
259 patients were recruited, mean age was 80 years. A direct repair without mesh was performed in 62 (23.9%) patients. Explorative laparotomy was performed in 56 (21.6%) patients and bowel resection was necessary in 44 (17%). Mortality occurred in seven (2.8%) patients. Fifty-five (21.2%) patients developed complications, 12 of whom had a major one. At univariate and multivariate analyses, Charlson’s comorbidity index ≥ 6, altered mental status, and need for laparotomy were associated with major complications and mortality
Conclusion
Emergency surgery for complicated hernia is burdened by high morbidity and mortality in elderly patients. Preoperative comorbidity played a pivotal role in predicting complications and mortality and therefore Charlson’s comorbidity index could be adopted to select patients for elective operation
AX J1745.6-2901 is a high-inclination (eclipsing) neutron star low-mass X-ray binary (LMXB) located less than ~1.5 arcmin from Sgr A... Ongoing monitoring campaigns have targeted Sgr A... frequently ...and these observations also cover AX J1745.6-2901. We present here an X-ray analysis of AX J1745.6-2901 using a large data set of 38 XMM-Newton observations, including 11 which caught AX J1745.6-2901 in outburst. Fe K absorption is clearly seen when AX J1745.6-2901 is in the soft state, but disappears during the hard state. The variability of these absorption features does not appear to be due to changes in the ionizing continuum. The small Kα/Kβ ratio of the equivalent widths of the Fe XXV and Fe XXVIlines suggests that the column densities and turbulent velocities of the absorbing ionized plasma are in excess of N... ... 10... cm... and v... ... 500 km s... These findings strongly support a connection between the wind (Fe K absorber) and the accretion state of the binary. These results reveal strong similarities between AX J1745.6-2901 and the eclipsing neutron star LMXB, EXO 0748-676, as well as with high-inclination black hole binaries, where winds (traced by the same Fe K absorption features) are observed only during the accretion-disc-dominated soft states, and disappear during the hard states characterized by jet emission. (ProQuest: ... denotes formulae/symbols omitted.)
Multiwavelength campaign on Mrk 509 Costantini, E; Kriss, G; Kaastra, J S ...
Astronomy and astrophysics (Berlin),
11/2016, Letnik:
595
Journal Article
Recenzirano
Odprti dostop
Aims. We model the broad emission lines present in the optical, UV, and X-ray spectra of Mrk 509, a bright type 1 Seyfert galaxy. The broad lines were simultaneously observed during a large ...multiwavelength campaign, using the XMM-Newton-OM for the optical lines, HST-COS for the UV lines, and XMM-Newton-RGS and Epic for the X-ray lines. We also used FUSE archival data for the broad lines observed in the far-ultraviolet. The goal is to find a physical connection among the lines measured at different wavelengths and to determine the size and the distance from the central source of the emitting gas components. Methods. We used the Locally Optimally emission Cloud (LOC) model which interprets the emissivity of the broad line region (BLR) as regulated by power law distributions of both gas density and distances from the central source. Results. We find that one LOC component cannot model all the lines simultaneously. In particular, we find that the X-ray and UV lines may likely originate in the more internal part of the AGN at radii in the range ~5 x 10 super(14)-3 x 10 super(17)cm, while the optical lines and part of the UV lines may likely originate farther out at radii ~3 x 10 super(17)-3 x 10 super(18)cm. These two gas components are parametrized by a radial distribution of the luminosities with a slope gamma of ~1.15 and ~1.10, respectively, both of them covering at least 60% of the source. This simple parametrization points to a structured broad line region where the higher ionized emission comes from closer in, while the emission of the low-ionization lines is more concentrated in the outskirts of the broad line region.
•Preheaters are used to trigger boiling, preventing superheating in cooling pipes.•A semi-empirical model for the preheater design is proposed.•The model validation closely matches the trends from ...experimental results.•The model is, in principle, applicable to any pure refrigerant fluid.
The fluid properties of CO2 make it an ideal medium for the cooling of tracking detectors in experiments at particle accelerators. Detectors such as the Compact Muon Solenoid Outer Tracker at CERN will be cooled to a nominal temperature of -35 °C with CO2 cooling to ensure the longevity of the silicon sensors. In theory, two-phase CO2 cooling results in a very low temperature change along the detector tube, dependent only on pressure drop. Experimentally, however, superheating – the existence of a fluid in the liquid form above its boiling temperature – has been observed to occur frequently. This results in higher fluid temperatures and a poor heat transfer coefficient over the first section of the detector tube, disrupting the cooling performance of the detector and possibly leading to deterioration of the silicon sensors. In order to prevent superheating, a preheater is proposed to trigger nucleate boiling in the Compact Muon Solenoid Outer Tracker detector cooling tube just upstream of the sensors. A theoretical – semi-empirical – model for the preheater design is presented, starting from experimental data points. With this model, the triggering of nucleation can be characterised for tubes made of the same material as that tested and with the same surface cavity size. The model validation is promising, closely matching the trends from experimental results, and giving preheater specific powers significantly lower than those derived from spinodal theory.
Gaia Data Release 2 Lindegren, L.; Hernández, J.; Bombrun, A. ...
Astronomy and astrophysics (Berlin),
08/2018, Letnik:
616
Journal Article
Recenzirano
Odprti dostop
Context. Gaia
Data Release 2 (
Gaia
DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the European Space Agency
Gaia
satellite during ...the first 22 months of its operational phase.
Aims.
We describe the input data, models, and processing used for the astrometric content of
Gaia
DR2, and the validation of these resultsperformed within the astrometry task.
Methods.
Some 320 billion centroid positions from the pre-processed astrometric CCD observations were used to estimate the five astrometric parameters (positions, parallaxes, and proper motions) for 1332 million sources, and approximate positions at the reference epoch J2015.5 for an additional 361 million mostly faint sources. These data were calculated in two steps. First, the satellite attitude and the astrometric calibration parameters of the CCDs were obtained in an astrometric global iterative solution for 16 million selected sources, using about 1% of the input data. This primary solution was tied to the extragalactic International Celestial Reference System (ICRS) by means of quasars. The resulting attitude and calibration were then used to calculate the astrometric parameters of all the sources. Special validation solutions were used to characterise the random and systematic errors in parallax and proper motion.
Results.
For the sources with five-parameter astrometric solutions, the median uncertainty in parallax and position at the reference epoch J2015.5 is about 0.04 mas for bright (
G
< 14 mag) sources, 0.1 mas at
G
= 17 mag, and 0.7 masat
G
= 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr
−1
, respectively.The optical reference frame defined by
Gaia
DR2 is aligned with ICRS and is non-rotating with respect to the quasars to within 0.15 mas yr
−1
. From the quasars and validation solutions we estimate that systematics in the parallaxes depending on position, magnitude, and colour are generally below 0.1 mas, but the parallaxes are on the whole too small by about 0.03 mas. Significant spatial correlations of up to 0.04 mas in parallax and 0.07 mas yr
−1
in proper motion are seen on small (< 1 deg) and intermediate (20 deg) angular scales. Important statistics and information for the users of the
Gaia
DR2 astrometry are given in the appendices.
Background:
The few epidemiological data available in literature on neuroendocrine tumors (NET) are mainly based on Registry databases, missing therefore details on their clinical and natural ...history.
Aim:
To investigate epidemiology, clinical presentation, and natural history of NET.
Design and setting:
A large national retrospective survey was conducted in 13 Italian referral centers. Among 1203 NET, 820 originating in the thorax (T-NET), in the gastro-entero-pancreatic tract (GEP-NET) or metastatic NET of unknown primary origin (U-NET) were enrolled in the study.
Results:
93% had a sporadic and 7% a multiple endocrine neoplasia type 1 (MEN1)-associated tumor; 63% were GEP-NET, 33% T-NET, 4% U-NET. Pancreas and lung were the commonest primary sites. Poorly differentiated carcinomas were <10%, all sporadic. The incidence of NET had a linear increase from 1990 to 2007 in all the centers. The mean age at diagnosis was 60.0±16.4 yr, significantly anticipated in MEN1 patients (47.7±16.5 yr). Association with cigarette smoking and other non-NET cancer were more prevalent than in the general Italian population. The first symptoms of the disease were related to tumor burden in 46%, endocrine syndrome in 23%, while the diagnosis was fortuity in 29%. Insulin (37%) and serotonin (35%) were the most common hormonal hyper-secretions. An advanced tumor stage was found in 42%, more frequently in the gut and thymus. No differences in the overall survival was observed between T-NET and GEP-NET and between sporadic and MEN1 -associated tumors at 10 yr from diagnosis, while survival probability was dramatically reduced in U-NET.
Conclusions:
The data obtained from this study furnish relevant information on epidemiology, natural history, and clinico-pathological features of NET, not available from the few published Register studies.
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